View Full Version : Have you Decked the cylinder

02-15-2002, 05:40 PM
I am doing a 440ex for my buddy. We found that the wiseco piston that came in the kit was about .040" in the hole giving us a quench of .073" and a compression ratio of about 9.5:1. It is labeled as a 11:1 kit. We cut the deck of the cylinder down to give us 0" deck, which in turn yeilds .040 squish and a comp ratio of 10.35:1. Will cutting this .040" off cause a problem with the timing chain tensioner? Has any one else noticed the advertised comp ratios to be that far off? Let me know what you think, Thanks

02-15-2002, 06:35 PM
Check out Mickey Dunlap's tech article. He says pretty much the same thing except I don't recall anyone talking about decking the cylinder. Can't see how 30-40 thou. would cause much problem with the tensioner though.

02-16-2002, 06:08 AM
I just read what Dunlap had to say. He was right on, the piston was exactly .043" in the hole, same as stock. He did not mention anything about the timing chain so I am guessing that there will not be a problem.

Matt Fisher
02-16-2002, 09:38 AM
Decking the cylinder, thinner gaskets, etc. will all cause the cam's timing to be retarded. Not stupid:D , retarded. Thicker gaskets will advance the cam. The cam tensioners position makes it all happen.

Get a degree wheel and check it. You can slot the holes in the cam gear to advance or retard the cam.

Good info about the Wiseco piston. When I do the Ross one in my bike I'll post the results. They say 11.2:1 using XR gaskets, and that the piston is .025 down in the hole.

02-16-2002, 10:08 AM
Yes, the Wiseco 440 11:1 piston has the same pin height as the stock piston, hence the same deck height. It took .003-.005" to deck the cylinder after the sleeve installation. Deck height is now .040". Pretty close to what OnOneWheel measured. Cometic makes a .025" thk. coated stainless gasket. With that gasket the comp. is 9.8:1. Take another .030" off the deck and you get 10.8:1 >>>much better! Wiseco must have calculated the 11:1 number assuming a "0" deck height. Guess I'll go back and deck it another .030" or so and check the cam timing - should be retarded about 1.5 deg. I'll post all the actual numbers later. As a side note, Honda is right on with their 9.1:1 stock figure!

Matt Fisher: Does that Ross piston have a dome, or is it a flat top?
The Wiseco 440 11:1 piston, pin, rings & clips weigh 402 grams total, stock was 383.

02-16-2002, 10:29 AM
Good info guys, thanks I actually didn't even think about the cam timing. I have a degree wheel so I will check it out before we run it.

Matt Fisher
02-16-2002, 08:38 PM
Mike, it'll be a couple more weeks before it gets here. I ordered 4 custom 89mm ones. Light milling around the pin boss area, special lightweight wrist pin. It'll weigh the same as a stocker, give or take a gram or two. I could have had it even lighter, but am unwilling to sacrifice strength, and by keeping it close to the stock weight, there's no balance issues. I'll also be polishing the entire piston before dropping it in.

Honda Jim (who designed JE's 440 piston) says it'll be an 11.2:1 using XR gaskets. I'll spec everything out when it arrives.

Why not use the thin Cometec head gasket, and no base gasket; just some sealant? Skip another trip to the machine shop. Plus, it's he11 adding metal later:D

Ononewheel: When you degree everything, check the valve clearances with the cam advanced and retarded, that way you can fool with the timing without worry. There's more power hiding in these motors, we just need to keep looking.

This is the kind of tech that's woefully missing from most boards, excepting some automotive ones I've followed. Good stuff!

02-16-2002, 09:45 PM
how do you degree in the xr400 cam?

02-17-2002, 07:30 AM
Disho1, that is a good question. All automotive cam manufacturers give you a spec sheet that will tell you when everything is supposed to happen. Trouble is for some unkown reason the folks that are selling these quad cams are greedy with the specs, you can get lift and duration but after that you are pulling teeth. Web is the only one I saw that would give lobe centers but that is it. I am sorry I do not have a good answer for you. But try this, go to a performance shop for cars and get a book about building motors and it should tell you all about degreeing.
Oh, and Matt you rule dude. Are you into racecars? You are right about more of this stuff needing to be posted, there is so much free horspower in engine building it's shocking. The only reason we decked it instead of using thin gaskets is because we have access to a head broach and gaskets cost us more money and time. We are going to clay it up and see what we got. I am concerned that if we have to oblong the holes to advance the cam, it will be in the direction that it will slip back and fall off. Do you have any ideas? I will let you guys know what we find out we are waing on the cam to come so we are on hold right now.

Matt Fisher
02-17-2002, 09:27 AM
DISH01 here's a simplified version- a disk (degree wheel) is attached to the cranks end, and it's marked for 360 degrees. You find piston Top Dead Center (TDC), and position a pointer so that it points to 0 while the piston is at TDC. Next you use a dial indicator on the camshaft, finding the center of the lobe. Look were the pointer is on the degree wheel. If you have a Megacycle 196-x2 cam, it should be at 107 degrees, since that's where Megacycle claims it should be. If it's not, or if you wanted to advance or retard it, slot the cam sprocket and set it where you want. The problem is that many of the cams out there don't have the specs available. Somewhat uncharted territory.

Ononewheel, I've done some work in the Mustang field. Mostly, I pay close attention to what knowledgeable folks have to say.

I remember that some aftermarket cam sprokckets for Honda's/Acura's don't have anything besides the tension of the bolts to hold it still. You could always make some bushings to take up the space in the slot if that doesn't leave you feeling warm and fuzzy. On automotive applications, if advancing or retarding the cam more than 6 degrees results in the best performance, you're not running the right cam.

02-18-2002, 02:50 PM
OnOneWheel: How does that 440 "short deck" run? Also, which cam did you go with?

02-18-2002, 03:13 PM
I am still waitng on the cam to come. It is a TC racing cam, but I am not sure if I am going to use it because it is on back order and i am sick of waiting. So if it does not get here quick I will be getting another cam elsewhere. No offense to T.C.. As soon as I can get this thing going I will start a new thread with all of the information, parts and specs as well as how it runs.:D :devil

02-18-2002, 04:07 PM
Ononewheel, did you Order the Cam from TC? Rocky Ridge Racing is a TC Dealer and Sells all of TC`s Parts. You should call and ask them if they have any Cams. What kind did you get, MX or XC?

02-19-2002, 06:40 AM
It's the xc, straight from tc. Trouble is.... he has the core already.

02-19-2002, 07:04 AM
Matt. Actually it's easier to put the metal back on for me! One of the things we do here is plasma spray; anything from plastics to carbides to ceramics to stainless... The problem here is that our machining capability is archaic, I have to go to friends shops to use the CNC stuff!

Matt Fisher
02-19-2002, 08:27 AM
Very cool Mike. Having the ability to add metal is great.
I have little to no knowledge of plasma spray. Could you educate me a bit?

02-19-2002, 06:41 PM
I noticed in your sig. that you've got a somewhat similar setup to mine. I just put the comp core in my exhaust replacing the quiet core and s/a. It wasn't too much louder and there was a significant increase in power across the board. If a little more noise isn't a problem, try it and see what you think. BTW- I didn't need to make any other changes. :D

02-19-2002, 07:17 PM
2slow, Thanks! I'll try that soon - The bike is still apart from putting the 440 & cam in it. I modified the quiet core some, it didn't seem any louder but it did pull harder - not hard to do if you're interested. Did you take the S/A screen out too?

03-04-2002, 05:05 PM
Keeping it near the top, good info here. Lets not let it get buried

03-04-2002, 08:20 PM
Back to cam specs.

I put in a wb all-around cam in and the specs were a little different than what I measured. They were pretty close so I'm unsure about my accuracy.

Intake- .341 lift, 240 at .50
Exhaust- .335 lift, 248 at .50
107 lobe centers

I didn't write down the open/close degrees or the valve overlap (I'm cind a retarted) but seems like 15 deg. overlap sounds familar.

Doubt this info will matter but would be interesting to get accurate specs on all the popular cams and compare them and cost. :D

Matt Fisher
03-04-2002, 09:31 PM
Everything you spec'd out looks correct except the intake lift is listed at .345. Purdy durn close...

I talked to Web today, all 3 of their cams have a LCA of 107.

All of the cams I have specs for have LCA's of about 107. The lowest is 105 for Megacycles 196-1 (intake side), and the highest is 108 for the stock exhaust.

03-04-2002, 09:53 PM
Just a question as you guys seem to have some good input on this subject.

I have a 11:1 piston in my 440 with the std honda gaskets and currently no other internal motor mods.

The engine does run strong but just doesnt seem 100%. I know that it could use a cam and I am looking into one (this post has been a great help thanx) but after talking with the orig owner and checking out some of the posts on the net I am a little confused.

To get the compression up (which by everyones thoughts seems to be the main problem) would it be better to use the thinner cometic or xr400 base and head gaskets or have it decked or both.

I will add that since I will be doing a comp and leak down test this weekend I am only assuming that there are no major ring to cyl wall wear problems based on the way it runs now.


Matt Fisher
03-04-2002, 10:21 PM
Whoa. Stock head gasket? Isn't it hanging off into the cylinder? This could be a problem...

You will need to check your chamber volume to find out your actual CR. Vary gasket sizes to achieve the correct CR.

Cometec makes head gaskets as thin as .025. Assuming your cylinder and cases are perfectly straight, you could seal them up with Honda Bond, or Cometec can get you a base gasket as thin as .010.

If you spend the time to get a real 11:1, and follow it up with a good cam (not an XR cam on a 440), I'll bet you get a bigger power gain than when you originally did the 440.

03-04-2002, 10:47 PM

thanks fr they reply.

I did not do the 440 so I can only hope that the gasket is not into the bore. I do believe that the previous owner did mean stock honda thickness on the gasket.

Are there any concerns with the thinner gaskets????

I am intending on obtaining the cyl volume when finished to help with fuel or octane requirements. Any ideas on octane if i do get it around 11:1 ?

Also do you guys have any preference on the cometec .010 gasket v/s honda bond ??

Any recomondation on a cam for this set up? I do like the bottom end stump pullin torque but would like more on th emid and maybe even a bit more on top.

Also where is a good place to get cometec.


03-05-2002, 06:32 AM
440exforme, I am not quite as good as Matt seems to be but here is my thought on the subject. Gaskets are probably easier than decking however you are limited to what you can change because can only get so many different gasket thicknesses. I also do not much care for steel shim gaskets....They work I just don't like em. With decking you would not have this problem, but the big draw back with decking is that most of us do not have access to one of those plasma things Mike400ex talked about so once you cut it it's cut, but so what, you will always be able to get a piston to fit. If your measurments allow I would try to use honda bond or yamabond on the base gasket. I only decked mine I did not do the gaskets so I am not an expert on that but it should work. Now... if the gasket thing does not get you a nice .040" quench area, decking is the only way to go, and put the regular gaskets in. You can get cometics at pretty much every shop, but call cometic and ask them about compressed thickness for the head gasket....very important... As far as cam goes I used the TC GNCC cam and I like it I had a Rocky Ridge cross country cam on a 400 and it was good too but I think the TC is better. TC makes power everywhere. I had trouble getting a cam from tc though it took forever. As far as gas goes I fired up the 440 I'm talking about, this last weekend. It has a comp ratio of 10.8:1. We put cam2 in for the start up because we wanted to be on the safe side of detonation. In car motors 10.6:1 is pretty much ragged edge for pump gas, I know motorcycles can handle more because of the aluminum motors allow heat to be dissapated better. We are going to start weening it off of cam 2 while keeping a close eye to see if there are any problems. If you do all that we are all talking about here you will be pulling stumps and beating up your rev limiter in no time at all....it won't even seem like the same bike.
440exforme, I hope that is at least a little bit useful. Sorry, once I get going...... Any how good luck and do not forget to post DETAILED results for all of us to see.

03-05-2002, 10:26 AM
Thanks for the info.

I have found that both the gaskets and decking are not too expensive so I will need to make up my mind which way to go.

I have a call in to cometic and will see what they have to say.

I think the cam will be the more diffilcult deccision now.

Also should I be worried about the timing? or degreeing the cam?? I hope not. have enough to worry about already;)

Also has anyone found any big advantage to valve work at this stage? I know there is an increase just not sure if its worth it on one.


03-05-2002, 07:24 PM
I'm going to take the motor back apart this weekend and take the stock base gasket out and install the xr head gasket.
I'll post the measurements between that and stock gaskets for everyone to look at when I get done. Maybe that will help clarify some peoples' confusion. :p

Matt Fisher
03-05-2002, 08:00 PM
The steel shim gasket is 3 piece, good stuff. The base gasket is far less important, not being in the combustion chamber and all.

For cams, here's a list of cams that might fit your needs, in increasing size:

1: White Bros all around- a bit more lift than the XR, but similar duration. 345 .335 240 248 @ .050
2: Megacycle 196-X1- increased lift and duration over the WB all around. .346 .346 246 246 @ .040
3: Web 450/451- still a great all-around cam. .350 .345 256 256 @ .050 This one increases the duration over the 196-X1, without increasing the lift much. This is a very popular drop-in cam, as it is also marketed by GT Thunder, and White Bros as their Track cam.

#1 will certainly have more mid and top than the stocker, but would still have tremendous bottom-end torque.

I have #3, albiet with a 12.5:1 stock bore. Still has good low-end, but the midrange hit is excellent. Very nice top-end.

Although there's nothing inherintly wrong with the cams from any of the tuners, I sure as he1l won't buy something without knowing what I'm actually getting...

You could certainly do some cleanup port work, couldn't hurt.

03-05-2002, 08:01 PM
how much clearance should there be between the piston and valves on the 400ex?

03-05-2002, 08:13 PM
I like to see around .100, you could go a little less (.080) but I wouldn't risk less than that. Let's see what the other guys think on this.

03-05-2002, 09:31 PM
Those are safe clearances, given the 400EX has sub-rockers to contend with. I wouldn't go less .080" with a hi-rev ignition box though. A good direct acting cam set-up, without rocker arms, can get away with a lot less. I just finished putting in a GTT cam last weekend. As a "quick & dirty" clearance check, I adjusted the valve lash to spec., then individually put a .100" shim in between and slowly turned the motor over (w/o spark plug!). Nothing touched so I got a good feeling that piston to valve clearance would not be a problem. If you ever do it that way, NEVER use a ratchet handle to turn the crank. ALWAYS use a fixed handle, such as a breaker bar and turn the motor very slowly. Sometimes when a valve is closing there is enough pressure to spin the crank with it and a regular ratchet will not offer any resistance. If there's not enough piston/valve clearance you will probably bend a valve! Also check one valve at a time. If any of the valves are canted towards each other (on the big end) they can touch, again resulting in bent parts. It's a relatively easy way to set your mind at ease. BTW, that was with a decked cylinder (piston now even with gasket surface). Also noticed that the Wiseco 440 piston had larger than stock diameter valve notches, so oversize valves wouldn't be a problem either. >>>>>Be careful and check when putting a shim in there, I remembered that I used a Honda car valve stem seal which was much shorter on top than the one Marcum's sells. Don't want anyone to ruin their valve seals.

03-06-2002, 08:24 AM
Cometic base and head gasket ?

I finally spoke with Cometic and they had offered the following.

Cometic base gasket @ .010 or .012 v/s .020 stk.
Cometic head gasket @ .025 v/s .040 stk
Note: over 12:1 they recomend their .027 w/cyl reinforcing ring to handle the extra forces from the added compression. They also addressed the the issue of the spacing of head bolts being too large and thats why they recomend the .027 w/ higher comp.

Does anyone know where I will end up if I go with the .010 base and .025 head gaskets. With out any actual measurements and just going with what I have read and heard I think maybe this reduction of .025 should put me damn close to the numbers were looking for.

I dont know or maybe I should just find someone here in NJ who can deck the head and just use the stk gasket(thickness).

Also should I just look into a higher comp piston? Like a 12:1 or ?

And thanks for the cam info.

03-06-2002, 09:17 AM
440EX4ME, assuming you have a Wiseco 440 11:1 piston. With a .025 head gasket, the .010 base and w/o decking the cylinder (approx. .033 in the hole) yields 10.0:1 compression. Un-modified head is 38.0 CC. Double check your actual deck height. The sleeves come long on the top step so you have to machine the top flat across. Normally some material is also removed fom the whole top face/deck. Machine the cylinder .030" (piston now down .003) and you will end up w/exactly 11.0:1. Most automotive shops can deck the cylinder. If you make a substantial ring to bolt the cylinder base to, you can use a lathe. A miller will also work if you just bolt the cylinder down. Always use a spacer on the base - never put any force on the sleeve. I checked the head bolt height, it was marginal having decked the cylinder .040". Make sure the head bolts are torqued down properly. Using a flat ground bottom tap would probably reduce the installed head bolt height if you run into a problem. Hope this helps some! You'll be very happy with the results if you take the time to get it all done right. I'm convinced this compression problem is the main reason sooooo many people think a 416 will out perform a similarily equipped 440.

Matt Fisher
03-06-2002, 05:54 PM
440EX4ME, unless you really want the Wiseco piston, you may want to wait until my Ross ones arrive. They claim to have 11.2:1 using standard thickness XR gaskets, so milling might not be needed. I'll post the results when I get them.

Also- call Allen at Advanced Sleeve 440-354-3440 and order their sleeve and gasket kit. The sleeve is only $46.18, and the Cometic gasket set is only $16.00. The gasket set includes a stanless head gasket, fiber base gasket, timing chain tensioner gasket, and 4 o-rings for the cam cover. I'll double check with Cometic, but the compressed thicknesses should be .025 for the head, and .018 for the base. LA Sleeve wants $75 for their sleeve, btw.

03-06-2002, 08:45 PM
I was told by the original owner that the piston is a J&E 11:1 89mm 440.

Mike I am a little hesitant to use a auto type machine shop as opposed to someone who deals with the motorcycle type al head all the time. Is this thinking right???

Also am I understanding you correctly that the new sleeve for the larger bore is longer or taller than the cyl section?? could it be slightly into the head when installed and if so by how much?? That does not sound like it should be that way.

I do not know what exactly was done to this motor but I was told that the cyl sect was originally in a 99 and somehow the last guy pulled the piston and cyl out and swapped it with his brand new 01 motor. They claimed to use gaskets with the stock thickness from Honda. So I do not even know how much time is on the piston and sleeve but would rather keep them than pay for new unless something is worn or maybe for a higher comp set up that would not require so much thought LOL.

I had to re read both your and matts last posts as I was getting a little mixed up but if I am hearing you right if I have the cylinder decked .030 it will remove the overhang on the sleeve and with the .025 and .010 gasket Iit should be around 10:1 ?

And after living this 440 ordeal I have to agree that it is the reason for the smaller bore confusion. It could have been avoided if the piston mfg had used a different pin height. IMHO

I do not have any loyalty to one piston mfg and would entertain any that show me an advantage etc.

Please tell me lore about the ross ones that your waiting on. Hmmm what would we get with the ross and the thinner gaskets??????

I will contact advance sleeve but I would think if I change the sleeve(maybe good idea for the price) I would change the rings as well and you know what the next question is Which rings to use.

Cometic did claim the .025 and .012 and added that the base does not compress. Also that these must be order individual and are not part of a kit.


PS I was thinking that the cams you had recomended earlier did not require hard facing the rockers.

03-06-2002, 09:52 PM
440ex4me, I too would trust the machine shop that had more experience in the motorcycle line of work., but it shouldn't be a hard job for either. I've found that most of the motorcycle shops sub their machine work to the automotive guys anyway.

There is a counterbore in the top of the 400EX aluminum cylinder w/o the sleeve installed. All the replacement, and also stock, sleeves have a step or shoulder at the top of the sleeve OD that fits into the cylinder counterbore. The sleeve mfg's leave about .010" extra length on the top shoulder to allow for any variations when machining the sleeve/cylinder top surface flat across. I didn't mean that the sleeve protrudes into the head - sorry.

I wrongly assumed that you have a Wiseco piston since you are having a hard time getting the correct compression ratio. The numbers I quoted were for the Wiseco piston and won't apply to the JE one. If you tell us the pin height, dome volume and valve notch volumes for the JE 89mm piston we can compare the two and see what you have. If I get a chance tomorrow, I'll call JE and ask them.

I ordered the Cometic top-end kit #C7826 directly from them and it came with the thin .012" non-compressable type base gasket and the .025 coated stainless steel head gasket. The Honda base gasket compressed was about .020".

03-07-2002, 08:43 AM
Sorry but I do not have the J&E info as all I know is that I think "its in there":)

I am researching to find someone local to NJ to maybe get it decked.

Matt Fisher
03-07-2002, 09:38 AM
Oops, had a "senior moment" there 440EX4Me. Forgot you already had the 440. Duh. I certainly wouldn't change the sleeve unless there was something wrong with it.

Any decent machine shop should be able to handle anything we've discussed here.

Instead of tearing everything apart, why not just cc your motor, as described by Mickey Dunlap's latest post here?

On hardfacing: Web makes the 450/451, the same cam as GT Thunder's, and WBros Track. While GTT and WBros say it's a drop in cam, Web says you must hardface the rockers. So who's right? :confused: I suspect that unless you use an OEM Honda cam, you're taking a risk. All 3 that I listed error on the safe side. As the man says "ya' pays yer money and takes yer chances".

Just got off the phone with Cometic tech. Their 3 piece steel head gaskets don't compress. The fiber gaskets will compress, the base one about 10%. Using kit C7826 (the one I got from Advanced Sleeve), there's a .025 3 piece steel head gasket, and the .020 fiber base gasket will compress to .018.

I custom ordered some Ross pistons (minimum order of 4 when custom work is being done) to do my 440 motor. All 4 are taken, btw. The Ross piston is slightly lighter than the JE or Wiseco pistons, and I was able to order a special lightweight alloy wrist pin. The custom work involves removing about 10 grams of metal around the pin boss area. When it's all done, the total weight of the Ross assembly will be the same as a stocker, give or take a gram. The Ross rep, Honda Jim, also noted some advantages over the JE piston. Bigger valve pockets, better ductile iron moly rings, etc. And since he designed the JE piston when he worked there, I'm inclined to believe him. When they arrive, I'll be able to compare them to a Wiseco that I have sitting here. No JE currently available to compare it to though.

03-07-2002, 10:22 AM
Matt, inspection of my GTT (450/451) cam didn't show any tell-tale signs of hardfacing (weld mat'l. on the sides of the lobes). Looks like it was just ground to a smaller base circle. The hardness was within 3 points on the Rc scale of stock. I only checked them on the base circle side to avoid putting "pits" on the pressure/rub surfaces, as most all of the hardfaced cams I've looked at were welded all the way around (eliminates some distortion). If you still have the head cover off take a look at the sides of the lobes on your cam - just curious. Also, the base gasket in the C7826 kit I received was about .010"/.012" thk. and would not compress much.

440Ex4Me, Don Scinto Automotive, 1269 Barnum Ave, Stratford, CT 06614 is familiar with doing this sort of work. I made him his fixtures. DSA is only one day UPS from Jersey. P.S. Tell him Mike Minner referred you.

03-07-2002, 10:04 PM
Wow with all this talk of deck heights and the like I am thinking I had missed something. Well I think I found it.

Do any of the piston manufacturers produce their pistons with a wrist pin to deck height that will allow the motor to achieve the proper compression ratio ( as stated by themselves) with the standard OEM gaskets?

This would solve the problem pronto and avoid all the BS. Wow I cant believe this. I have decked v/8 big block chevys in the past because you got some great gains, but I do not remember coming up this short on compression before.

I guess im just getting a little frustrated cause I need to make up for the pistons shortcomings.

And thanks again for all the help.

03-08-2002, 08:25 AM
I have been reading this post when I can, Good info guys! Any way I have a question that nobody can seem to answer for me. I am wanting to run as close to 11:1 as I can in my 440. How do I check to see what compression I have right now? Do I have to take the head off and measure where the piston is?
Thanks for the help....:)

03-08-2002, 10:27 AM

To figure your true compression you need to measure the cc's of your cyl volume at tdc.

there was a very good explanation in the curtis sparks q&a but basic what you need to do is bring the cyl to TDC and fill the cyl with oil or another suitable liquid and measure how much fluid it takes in CC's (cc is easier as this is the unit used for your bore as well) add this figure to your bore (eg 440cc + 50cc) and then divide by the same volume number.

The example above would yeild a 9.6:1 which is about what I am expecting from mine.

Hope that helps.

03-08-2002, 10:48 AM
That's probably the most accurate - and the best way to get covered in oil! Don't use alcohol, a light motor oil works best. Also use the correct "engine size". I believe the IMS 440 kits usually come with a 88.5 mm JE piston (431 cc's) and the Wiseco kits are 89mm (435 cc's). Have fun getting the oil out after you're done.

03-08-2002, 02:27 PM
Thanks 440EX4me, I will try to do that tonight. I have another question for you all then. If these companies are advertising a 11:1 compression and it is only accually 9.5:1 or so. Has anyone looked at a higher compression piston to get closer to 11:1?
It was just a thought that I had...

03-08-2002, 02:56 PM
I'm hoping for everyone's sake it's only the Wiseco 440 piston that's advertised wrong. I've tried numerous times to get some info out of Wiseco about this and.................still holding.:mad:

Does anyone know if the JE 11:1 440 pistons have a dome?

03-08-2002, 04:48 PM
so if i run an xr headgasket and no base gasket with a weisco 440 piston do i get 11to1 or do i need to deck the cylinder some?:confused:

03-08-2002, 05:16 PM
I remember something about the JE 416 piston having a dome...ask knighttime..(i think thats who...) or vwvr6, they will probably know

Matt Fisher
03-08-2002, 08:13 PM
While I can't vouch for the JE, the Ross ones I ordered just showed up (ye haw)-and they do have a dome. Since the same guy that designed the JE ones also designed the Ross pistons, I'd suspect they do have a dome.

BTW, the top of the Wiseco 440 piston I have in my hand sticks up .030 higher than the stocker. I pushed a wrist pin through both pistons, and used the end of my dial calipers to check.

The Ross piston's dome starts from the stockers height and rises up .190

Hippy, I think the consensus is that you should end up at about 10:1 with a .010 base and a .025 head gasket... You won't get to 11:1 without visiting the machine shop.

Mike, I don't see any signs of welding on mine either.

03-08-2002, 08:57 PM
Yes, the JE "10.8:1" 87mm piston has a dome - I believe I have the specs at home if anyone is interested.

I assume that the 89mm JE is also domed, as the catalog I have shows it to be. I believe they use practically the same dome on all their "off the shelf" pistons, which also reflects in the compression rising as you go up in bore size with JE off the shelf pistons.

Great news on the Ross pistons Matt.... Have you weighed the assembly yet?

Matt Fisher
03-08-2002, 09:17 PM
You're quick Gabe, I was in the process of e-mailing you...

The pistons weigh 302 grams, a little more than I was expecting. This is off Ross's spec sheet, I have not taken the assembly down to the machine shop to have everything weighed. Do you want piston A or D?

They look great! Nice big valve reliefs, and the machine work appears to have been done on the skirts, not the pin boss area. They have oil galleys going to the wrist pin, the stocker and the Wiseco don't have this. Good stuff.

03-09-2002, 12:06 AM
My JE stock bore had oil galleys to the wrist pin and no dome, flat top. However, does anyone know how many cc's the valve reliefs are? I'm guessing around 6cc's. Didn't measure,don't know, just kind of looks like like about 6cc's.
Seems to me that the valve reliefs could be important when figuring true comp. ratio especially when the combustion chamber only measures around 38cc's ( at least that's what I've read). Even if it is only 4cc's it would make difference. :confused:

03-09-2002, 12:28 AM
OK-- sorry. Upon retrospect, I think my stock bore JE had a slight dome to it. ( I'm cind a retarted, no life, single parent, and women hate me).

Matt Fisher- I recall where some pro engine builders have found the Ross piston ( among others) to not have the piston pin alignment be exactly square with the bore and/or rod bearing. As much as .001 off. I know it's not a big deal but like all precision equipment it wouldn't hurt to check. BTW- I too like the semi-custom pistons from Ross, they are a work of art.

03-09-2002, 06:21 AM
Wiseco 440 piston differences? Mine has the same pin height as stock, w/in .0005"!

Took the bike back apart last night to check the head nuts. You definetly need to go back and retorque the composite head gaskets! The GTT cam and un-hardfaced rockers had no scuff marks or signs of failure at all. Will check after some time is on it.

What did the piston,pin,rings & clips weigh together Matt? I found the stock to be 383 gms. & the Wiseco 440 402 gms.

2slow, the Wiseco 440 and stock reliefs both are close enough to 1 cc total (all 4 combined).

03-09-2002, 06:03 PM
Just thought I would throw in a reply to move this up a little. This thread turned out to be the best thread I personally have ever read. Thank you all for all the input and questions that this brought. Is there somewhere this can be saved for future engine builders? It contains alot of very important information. Later for now.

03-09-2002, 06:57 PM
Thanks MIKE400EX!
Guess I just expected them to be larger. Shouldn't make much difference If it's just 1cc total. :D

03-10-2002, 02:34 AM
Yes I agree this maybe the best information I have read, thanks to all who contributed this valuable information for us future engine builders.
The moral of the story is, question everything and prove it to be what it is meant to be. It makes you wonder how many sub-par engines are out there that aren't running up to their intended potential. Those builders that use this information to correctly assemble their own motors will be many quad lengths ahead of those who don't know the real story.

Thanks again!!!!!!

03-12-2002, 09:48 PM
Guys this thread is without a doubt one of the most imformative I have seen yet and thanks.

I had an interesting talk with J&E the other day and it led to a few good talk with some tech people etc.

After calling J&E and speaking with their tech guy who was very easy to deal with I found out the following. First they claim to only manufacturer pistons for the EX400 (89mm 440) up to 10:1 under the J&E name. He had said that they do go up to 13:1 for IMS, and that he had little if any info on these and gave me IMS's #. I had imformed him of our discussion here and he had asked that I update him of my findings on the actuall compression numbers on any of their products.

After speaking with IMS they were not familiar with the actual installed compression of their product and had no info or suggestions in reference to deck heights or installed piston measurements, they did claim that there have been no negative feedback info on the compression issue.

IMS also had asked to update them on this issue as well. They did tell me that the 10 1/2:1 on up were dome top pistons with valve reliefs. IMS does offer a few interesting pistons for this application. the one that had stood out to me was a 13-1/2:1 89.5mm piston that was accompanied with the disclaimer that it could only be rebored once.

When I asked the tough questions about the decking and actual compression numbers thay had refered me to white Bro's as they not only sell their product but also have some experience with the set up through their race sponsorship.

I am still awaiting a call back from White Bro's and will update all with the info when they call back.

I guess what I am trying to do is see if I use a certain piston I can get away with just using the thinner gaskets and still get an acceptable compression ratio.

03-13-2002, 07:39 PM
Still no reply from White Bro's yet.

Will be doing std comp test and removing head thur night.

Will post all measurements that I get.

03-14-2002, 08:27 AM
First they claim to only manufacturer pistons for the EX400 (89mm 440) up to 10:1 under the J&E name.

That's odd, the JE catalog I have states otherwise....

Well, maybe he's technically right - my catalog only lists pistons for the XR400...

Matt Fisher
03-15-2002, 08:04 AM
Things may have changed now, but when JE's 89mm piston was developed, IMS had the exclusive.

03-16-2002, 12:53 AM

Thats basicly what J&E told me last week.

I still have not heard anything from WB so I am going to have to tear it down and measure it up.

will post the results.

03-16-2002, 01:35 PM
I'm thinking of ordering a 416 kit. what do you think about ordering it with the 11.1 piston (instead of the 10.8) so that I can use the XR400 head gasket, and the stock lower gasket, and still end up with a compression ratio of around 10.5 - 10.8 to 1 without having to worry about the deck height? Does that sound reasonable or not?

In other words, what would happen if I tell Marcum's to send me everything that they normally would, except substitute the 11.1 piston so that the compression ratio will be up around what was intended (10.8)?


03-18-2002, 08:41 AM
Leel, just be sure to measure everything. Getting the right quench is every bit as important as compression ratio if not more so. I really don't know anything about 416's. I am not sure if they have a deck height problem, only one way to find out....

03-18-2002, 01:36 PM
O.k What if I go with a JE 416 10.8:1 piston, with a stock base gasket and a xr 400 head gasket. Then get it decked, say .015 to .02"? what's the comp ratio going to be. How much can you deck and still be safe? Sorry for the dumb ?'s, I'm just trying to thing a something that will whip my cuz's 416.

Can you tell me what comp. rato he has. He's got a 11:1 wiseco 416 piston with stock gaskets, xr 400 cam, and a 39mm Fcr carb.

Here is what I was think of going with Je 416 10.8:1 piston, decking the jug and thinner gaskets, tc xc cam, modded stock carb. Does this sound good to you guys?


03-18-2002, 03:21 PM
MR HONDA EX'S, you (we) need to know some more data such as the piston pin height, dome volume, valve relief volume, comb. chamber vol., and installed deck height (of either the JE or OEM piston) to figure the "true" compression ratio.
As far as the comparison goes, need to know the "true" compression of his bike. Assuming it is 11:1, and from what has been posted here, the FCR will give you more of an advantage with the XR cam than the MX cam w/a modified stock carb.

03-18-2002, 04:01 PM
I'm don't sure what all the specs are on the JE pistion or the Wiseco are. Does anybody know? All I know about the wiseco in it's a 11:1 comp. ratio, it's just what ever they offer. Sorry I don't have specs. I guess what I'm asking it what would it take to get the JE to 10.8:1 or close too that comp. ratio. Because I think if I can get it close to 10.8:1, that I could have the better bike (motorwise) And with the right cam, it'll fly. I'm trying to do my homework before I do anything to the motor.

03-19-2002, 06:29 PM
Well started the tear down and so far only two problems 1) a few busted valve cover bolts (pain in the butt) 2) Had a cousin pass away (and I am worried about the bolts) and was not able to get any more into it.

I had some interesting talks with a few local machine shops. Most all wanted to shave the head as opposed to deck the cylinder. One even refused to do it any other way.

So since I am not really excited about mailing out my motor I am leaning to just getting the higher comp (13:1) piston and cometic gaskets (gaskets are on the way) and avoid the decking.

Well will post future findings on the J&E dims etc.

Also spoke with a local MC/ ATV guy and said he could get the specs on the J&E pin heights etc.

Also I am assumeing that the shaved head would be a bald oops bad thing

Matt Fisher
03-19-2002, 07:36 PM
Nice play on words..:)

I'm going to guess that the JE stuff isn't inheriently wrong like the Wiseco. Try using a syringe and oil to determine what CR you actually have before removing metal...

What CR are you shooting for, anyway?

Sorry to hear about the bolts, er, I mean your cousin.

03-19-2002, 08:11 PM
I replaced the stock head and base gasket last week and this is what I found:
The JE 10.8/1 piston had a deck ht. of .028
Compressed thickness of stock head gasket- .035
Compressed base gasket- .020

Compressed thickness- .025
Piston is now .006 of deck ht. with hi temp silicone instead of base gasket.

After putting it all back together, I sat down to figure actual comp ratio. Couldn't do it- I forgot to measure the DOME AREA. So I did the next best thing-I guessed. If the dome area is 3cc and the valve reliefs are 1cc: than I should be right around 10.6 to 10.7 ratio. Of course when you throw in tolerance stacking and guesswork it could be anywhere from 10.5-10.8

03-20-2002, 12:45 AM

At first I was thinking I would be happy to be close to the 11:1 that I thought I had :) But after thinking about it and obtaining a lot of info:confused: I might be looking for more like 12:1 +/-.

My current thought is if I go with the 13:1 and just change to the cometic gaskets I would expect 12:1 + as a final result and without removing any material from the cyl.

Using the 105 or 115 octane fuel is not a problem as it is avail local. It does smell better also reminds me of the drag race days in the past.

My new deal is now on cams. I have heard that Honda does hard face the OEM rockers though not as hard as the reworks. I tried to get the rockwell numbers for both ones but received dumb looks(you can tell this even over the phone) and no answers.

I do not want to go crazy with the duration as I would like to be able to keep as much of the bottom end punch as I can.

I will let you all know what I find when I cc the cyl and will measure the deck as well.


Its late here so I may be wrong but I am not sure that your method of finding the CR makes sense. but then it could be right on the mark.

Well I read it again and still not getting through my skull...sorry
Maybe use the method described above.

03-20-2002, 06:56 AM
400Ex rockers are not hard faced from the factory, at least mine were not. They are hard chrome (flash) plated, doubt if it's more than .002 thk. - but didn't want to cut up a rocker to find out!

Matt Fisher
03-20-2002, 07:58 AM
440EX4me: Check out the Web 479 cam. Less duration than the Web 450/451 (aka GT Thunder or WBros Track) cam, but with more lift. My buddy's going to be trying it out on non-hardfaced rockers soon enough. Using FST oil cooler though. When our motors are done, we'll know first hand the power differences with his 479 vs my 450/451 cam. Should have similar top-end, but the 479 should be better in the low and mid range, with better snap. I'm betting that the 479 will also benifit more from port work, given it's additional lift.

Funny- I'm going to a 440 to stop using race fuel. Driving 2 hours to pay $4.50 a gallon dosen't work for me. Out with the current 12.5:1, in with the 89mm 11:1...

The hardfacing involves removing about .050 material, welding a new pad on there with nickel boron alloy, and then grinding it back down to the stock height and curve (kids, don't try this at home on the grinder :D ).

03-20-2002, 08:31 AM
I know you guys are probably sick of hearing me preach about this but, I feel it cannot be left out. We have been mostly sticking on the issue of compression ratio... which is good. We all know compression = power. I want to stress the importance of quench and the power it produces or subtracts. Quench or squish is the term that describes the distance from the piston at top dead center to the surface of the head around the combustion chamber. The whole idea is to get this clearance as tight as possible to force all of the fuel mixture into the combustion chamber. This allows a faster and more efficient and complete burn, which makes horsepower. Of course there is a limit. The rod will stretch a little, there is some play in the motor and what this means is that if you do not have a big enough distance the piston will smack the head at high rpm's. The all known safe distance is .040". I have heard of tighter clearances but that is known to be safe and effective. I would not be scared of .039" or even .038" but I would not try to achieve that. I have heard of small block chevy's as tight as .024" BUT DON'T TRY IT, I'm just saying. Use whatever means possible to achieve this .040" while you are all adjusting your comp ratios. You can change gaskets and or deck the cylinder, milling the head has no effect. I think this is another one of the small lesser known things that makes the huge difference between to otherwise equal engines. With that said I feel alot better. Good luck and Happy horsepower hunting.

03-20-2002, 08:54 AM
Excellent arguement for trying to obtain the desired compression ratio using a flat top piston - no dome to get in the way. Flip side of the coin is that the popular 10.8/11:1 400EX pistons have a minimal dome anyway. Would make an interesting dyno test.

Matt Fisher
03-20-2002, 07:59 PM
Good point Jeff.
In theory, the 11:1 flattop will make more power than a domed 11:1. More importantly, the flattop has a lower chance of detonation, so you can run a higher CR, making more power.

There are a couple of issues though. With an OHC motor, there's the issue of cam retardation :huh , a cam chain that is "loose" sooner, as well as possibly having clearance issues with the studs as mentioned in this thread (I think it was this thread).

The lessened detonation issue is great, but how much more CR can you run? Given the dome on my Ross is only .190 tall, I'd suspect it's marginal.

The Ross piston I have seems to mirror the chamber design, that's also a good way to keep turbulance up in the chamber. With a standard car OHV motor (GM, Ford, etc.), getting a mirror image of the chamber on the piston isn't easy, but large squish areas are possible.

I'm guessing it won't make squat difference given the level of power development we're at. Mike's correct though, we really need some dyno time to really get it right...

03-20-2002, 10:40 PM
This post is great.
Thanks alot for bringing this useful info to the table.
This is the best post i have read by far.
It will help future engine builders definetly.

good job...and happy horsepower hunting.


03-21-2002, 07:08 PM
Glad to see this information is usefull.

03-21-2002, 07:19 PM

I was just trying to show the difference in gaskets and their relation to deck height. I got off track trying to explain that I couldn't accurately calculate my CR because I forgot to measure the piston dome volume. Sorry for the confusion, I should have simply said that I decreased the piston to deck clearance by .028 by using the xr head gasket and silicone for a base gasket. :D

03-21-2002, 10:15 PM
2slow, sorry to be confused:)

but as I said it was late here and may have had only one eye open anyhow:D

I think what I was trying to say was that I had similar intent as you but that without the cyl volume its not gonna happen.

But I do see where you were going now and let me know what you find in real CR anyhow.

MAtt, I had talked with web cam and they are claiming a min 2 week delay on their cams. I did try to discuss the 479 but ended up getting the info on line.

What other sources would be good to get the 479 or close equal. I was thinking I would be better off keeping the bottom and mid power up as much as I can since it will be mostly woods type riding/racing.

Matt Fisher
03-22-2002, 08:31 AM
None of the cams from Web, Megacycle, HRC, seem to have the lift of the 479 (.378) with it's smaller duration (250 @ .050). Megacycle makes one with the .378 lift, but it has a duration of 254 @ .040 (guessing 256 or so @ .050). I don't see an equal.

You could use WBros all around cam, but the .345 .335 240 248 specs aren't that much bigger than the XR's at .326 .321 240 244. The all-around is about the smallest that I'd consider running on a 440. Should have tremendous bottom-end though. Megacycle's 196-x1 runs .346 .346 246 246 @ .040 and would also be a good mild choice.

2 weeks huh? My buddy's gonna blow a gasket.

Since the tuners (TC, Sparks, etc.) won't disclose their cam specs, I'd say just run the 450/451. In stock at GT Thunder, WBros...
I really believe that many of the cams supplied by various tuners are really in fact off-the shelf items. Don't know for sure just yet though.

03-22-2002, 11:07 AM
Matt, The 479 is the WEB cam! (TYPO) The Megacycle cam with 254 deg.@ .040" is more like 250 @ .050" (also guessing) Must be too early yet in CA!:D

Ever notice that the WB all-around is just about a copy of the XR cam, and the GTT-WEB 450/451-WB Track are also very close to the HRC cam? Maybe Honda does know what runs best all along - or there are some cam grinders that don't want to put much effort into R&D of new grinds!

03-22-2002, 06:14 PM
Good thread..!

I was just going to slap my piston in and call it good enough.. but now...



03-22-2002, 06:54 PM
Leo, You still haven`t put your Piston and Cam in?

Make sure this goes in the FAQ Forum.

Matt Fisher
03-22-2002, 07:55 PM
Even with the specs we have, the ramp angles can really affect the powerband.

If I were designing a cam from scratch for this motor, I'd certainly pay attention to what Honda offered. Actually I'd make roller rockers with far more radical ramp angles. :D

My friend called Web today, the 479 is only a week out now. They said that the decompression mechanisim comes off, and you need to press the sprocket's flange off too. They only deal with the bare cam.

Why can't the decompression release be used? Same basic cam, I'm wondering if Honda's patent has anything to do with it...

The pressing on and off of the flange concerns me. Is it on there in such a fashion that it can't be pressed on at the wrong spot? Getting it pressed on and then finding out that it's off by a few degrees would really suck.

03-22-2002, 08:58 PM
The flange only goes on one way, it's got the "big tooth" syndrome. Make sure that the flange is seated against the shoulder on the cam completely before you put it back in. Otherwise the sprocket will run out (wobble) as it spins. BTW, the flange on my GTT was not seated properly.

I've also wondered why the decompression devices always get removed. I could see the removal if the cam gave a very lopey or rough idle, but I'd think a mild one would be OK?

Since we keep visiting the hardened rocker subject I'll share some findings based upon similar OEM auto design.
Use hard welded rockers if any of the following apply: 1. the cam is hard welded. 2. ramp angle (valve opening rate) is increased 3. higher RPM is expected (modified rev box) 4. running at sustained high rpm 5. higher pressure valve springs are used 6. the motor runs much hotter than stock 7. you run (the motor) on alcohol 8. you don't like to change your oil 9. the rockers are already worn out.
Shouldn't have to hard face them if none of the above and: 1. the cam is not hard faced or is of similar material and hardness as stock 2. stock springs are used 3. you've got a rollerized set-up. I'm sure I missed a few things but it's a start!

03-22-2002, 09:04 PM
Matt, the flange is splined & got one wide one so it can't be oriented incorrectly...

I'd also be interested to hear why the decompressor can't be used.

03-22-2002, 09:11 PM
Looks like you beat me to it Mike.

Here's a question on the hardweld rocker topic...

If you get your rockers hardwelded unnecessarily - and the cam is not, does the cam then become the wear item?

03-22-2002, 09:16 PM
matt, in some of the xr fourms i have read about the auto decompressor. the xr owners remove the auto decompessor from the cam for easy starting of there bikes ( xr400, 600, 650 ). they claim that by removing the decompressor it reduces valve train noise and some claim that the bike revs quicker. the main deal with removing the auto decompressor and not using it is there are two oil holes in the cam that oil the decompressor. the oil holes have to be welded up or there will be a loss of oil pressure to the other oil holes in the cam lobes. i would ask Web if they weld up the oil holes. i do not think Web or the other cam grinders weld the oil holes up. i am not sure but could this be the reason for hard weld rockers?

yes the flange is made so it can't be pressed on wrong.

also if the auto decompressor fails there are small rollers and springs in the one way clutch that would do some damage to the motor.

03-22-2002, 09:28 PM
Sorry, not trying to take any thunder away!

Yes, the cam would certainly become the "wear item".

I don't think it would matter much as long as the oil is kept clean. The hard chrome plating on the stock rockers is almost as hard as the welded type hard facing. It's just not very thick and once worn through (which could happen during break in - especially w/used rockers) the soft base will quickly gall and/or wear.

03-22-2002, 09:33 PM
So if I got a TC XC Cam that is a Drop-In that does not need Hardface Rockers, but I Hardfaced the Rockers anyways, the Cam would be the Wear Item?

03-22-2002, 09:42 PM
That would make the rockers harder than the cam, so the cam would theoretically wear quicker (wear item). I wouldn't worry about it though!

Would an XR be any easier starting if the kick starter kicked back and whacked your leg because you removed the decompressor? OUCH!

03-22-2002, 10:04 PM
So your saying I should just Drop it In and not worry about the Rockers?

03-23-2002, 02:59 AM
WEB grinds down the base circle to get higher lift so they cant keep the decompressor on.XR's start better with out them because you can find TDC and that's part of the trick to starting a kick start motor.You do'nt have to weld up the hole's in the cam.I have built a few motor's with out decompressor's and did'nt have any problem's but it would'nt hurt either.The main thing is to get good COOL oil to the hottest high load area which is the head on a RFVC motor.I'am running stock rocker's in CHAD DUVALL'S PRO 500 ex in the GNCC race's with a oil cooler that feed's cooler oil in to the end of the cam to prove this point.The stock rocker's are slicker than hard welded one's the only problem is RFVC motor's run so hot [more so when built] that when the motor is shut off the chroming cool's quicker then the rocker it;s self and it cause's the chroming to crack and flake off resulting in cam failure.

Matt Fisher
03-23-2002, 07:50 AM
Mickey, outstanding information on the flaking of the chrome, as well as the CR issues. Thank you.

03-23-2002, 07:53 PM
What would my compression be if if I took a 425 or 426 what ever it truly would be and put a 12to 1 piston kit or 12.5:1 piston in it with stock xr 400 gaskets the true compression would probably only be around 11.5 or 12:1 would that be safe to sayI would like to have true 11:1 or 11.5:1 ratio if at all possible

I also was wondering about cams I am going to get the head ported and polished 416 or 426 havent quite been convinced on which one to build eventually a fcr and a hetricks pipe Im a little indecisive on which acm to run I ve have told that the 450/451 is a awsome cam but lrd claims it makes to much top end and when it starts to work good you have to shift due to the 400ex running out of motor so I found this cam by HOT CAMS it s like 254 duration @.050 and the lift is .346 in.and .338 on the exhaust would this be a better cam for the 400 set up like I jsut listed above I NEED SOME HELP ON GETTING A MOTOR COMBO TOGETHER

03-23-2002, 07:57 PM
One more thing would I be better off just putting a je 10.8:1 piston in it and not worrying about the higher compression.

03-23-2002, 10:47 PM
I have been real busy and have not had the time to get the cyl volume so when I had a few free minutes earlier I just did a comp test with the trusty old auto type comp tester.

Well now I am almost afraid to open her up as the highest reading was about 95-98 psi. I do not have any tech info on the honda but I do on yamaha so I checked out the YFM350 warrior specs and they claimed 120+psi.

I know this is a pretty large difference in machines and the psi readings, but could anyone advise if this would indicate just a overly large volume or a mech problem.


03-24-2002, 10:30 AM
The stock comp # from the Clymer's manual is only 100 to 128 psi, your altitude/air density affects the numbers as I'm sure you know. Pretty pathetic #'s for a sport engine. :rolleyes:

03-24-2002, 06:02 PM
Power slider thanks for the numbers.

I am at approx 15ft above sea level so the air stays pretty dense.

And the reading were when it was well warmed up as well and the readings were hitting mostly in the 90psi and after repeated checks it was almost always right at 96psi.

It still runs well and even had it out today but it just is not right so will be taking it apart tue and see what we find.

Matt Fisher
03-24-2002, 09:47 PM
Odd, I replied to this thread this morning, not here though. Oh well.

I compared my friend's stock cam to my GT Thunder (Web 450/451), and they did weld up 2 of the holes.

Shook, saying the 450/451 cam is too big is too vague. Saying it's too big for an otherwise stock motor; probably. For a 13:1 505, not a chance. I'm currently running the 450/451 cam in my 12.5:1 stock displacement motor, and will continue to use it when the 11:1 440 piston goes in. I don't think it's too big, it's only a bit bigger than the HRC cam, and that's designed around a higher compression stock displacement motor. The Hot Cam you mentioned is about the same size as the HRC, btw.

Does Hot Cam have a website?

One very important consideration- how you're going to use the bike. TT racing and sand lend themselves to top-end cams, while screwing around pulling wheelies with your buddies doesn't. Are you racing, play riding...?

Unfortunately, the only piston that we seem to know the true CR is the Wiseco 89mm. It really gives 9.6:1. I will have specifics on the 89mm Ross quite soon, but if you want to insure the correct CR, then you'll need to check it. I would not suggest a 12.5:1 with thick gaskets, it wouldn't be the best setup for making power. The dome on a 12.5:1 is fairly tall, and will certainly impede the flame front, especially at the lower CR. Are you going to run race fuel?

I hope this helps. Could you throw a period or so in the paragraph? Makes it easier to read, understand, and respond correctly to.:)

03-24-2002, 10:14 PM
Thanks for you taking the time to reply.What I meant was when I was talking to LRD they said that the WEB cam is a good cam ,however they said that web grinds there cams and they do a slight mod to it.Now if they are full of it maybe sounds like a selling point to me.I was told that that cam works real well in the upper rpm ranges and that when it really starts to make power its time to shift.I would have to agree that on a larger displacement motor a larger cam would work well it only makes since that the bigcc motors need more cam to assist in the flow.

What in your opinion would be a better set up a 416 or 426. The web 450/451 cam or the hot cam.Oh by the way they dont that I know of but I do have a number(515)-402-8005if that helps.
Im going to send my head and jug to Hetricks to be ported and bored.I was thinking of just sticking with the 10.8:1 piston and like a 416, but have heard that the 426 is the better way to go.Im still uncertain if im should hard face the rockers or not the guy at Hetricks said it was not needed as long as I stay on my valve adjustments and keeop the oil changed,however web recommends it to be done but that is nothing but an insurance policy for them.Im then going to put the Hetrick pipe on it and either the 39 or 41 fcr.Then leave it alone.

My question on compression is that if what people are saying is right the 12.5:1 piston would probably work out to be 11:1 or slightly higher.That would be borderline on the race/ pump gas thing and definately add some serious torque.

Matt Fisher
03-25-2002, 08:24 AM
In my opinion, the 450/451 cam isn't too big, I actually feel that my bike has decent bottom-end, excellent mid-range, and a good top-end. I have found myself bouncing off the stock rev-limiter a couple of times, indicating that the power hasn't dropped off significantly yet. I can't comment on whether or not LRD has a special grind made for them, I would be a little surprised though.

You may want to check out the website for GT Thunder- http://www.geocities.com/gtthunder.geo/gt1.html There are a ton of dyno runs on there. Their cam is the 450/451, btw.

If you're comfortable with the thin cylinder wall of a 426, get it. It's the same price as the 416 and will make more power.

The FCR carb, Hetricks pipe, and port work will all work best in the upper rpm ranges anyway. Not poorly in the lower ranges, but a higher-rpm cam should compliment those mods quite well.

I think you're misunderstanding the CR issue. The only piston that always seems to have a lower than advertised CR is the Wiseco 89mm. The 86mm JE, the 88mm Wiseco or any other piston may very well give you the correct CR. If you purchase a 12.5:1 piston that really gives you 12.5:1, then MUCH thicker gaskets might bring it down to 11:1, but you'll make less power than a piston with a small dome (or flattop) and standard thickness gaskets. I'm thinking that the JE and Ross pistons will be more likely have to the correct CR since they have small domes.

03-27-2002, 06:12 PM
ref comp ratios

I finally measured the piston dome vol and came up with 10.89 CR using a stock bore JE 10.8 piston, xr head gasket, and silicone base gasket material.
The combustion chamber, valves, and piston have a thermal barrier coating on them, so that my have increased the CR slightly but not enough to make any difference.
Hope this helps! :)

03-28-2002, 07:25 AM
A couple more notes:

1.) Took the head off the EX to check the torque on the head gasket again (Cometic Fiber composition w/ SS fire ring). The first time I checked it after about 1 hr. run time, it needed to be re-torqued. This last time, after another 2 hrs. NO re-torque necessary. Good idea to go back and check it if you have a composition type gskt.

2.) The holes that are left exposed after removing the de-compressor do not go thru into the oil passage, so there's no need to weld them up. No oil loss there!

3.) Honda puts a paint mark/indicator on the end of the outer valve spring that goes up (wider spaced coils). They do not mark the inner coil.

03-28-2002, 08:58 AM

03-28-2002, 09:01 AM
The FCR carb, Hetricks pipe, and port work will all work best in the upper rpm ranges anyway.

Actually, Matt, I noticed more bottom end gain with the FCR than I ever expected (actually I was expecting to lose a little bottom)... That's going by the seat of the pants dyno.

Must have something to do with less disruptions in the air path than the stock carb (Really, it has none, the stock carb has two)... But there was a large difference in the low end & mid with the FCR. I didn't notice much on top, but my limiting factor I'm sure is the cam I run. I'm sure there would be a huge diff in top end with a more aggressive cam - we've got one engine like mine with the GTT cam, but never ran it on the stock carb - mine's been run on both.

04-02-2002, 01:38 PM
Hey guys I finally had some time to get into this engine and have some interesting findings.

Well it is truely a J&E flat top piston in there and it was looking like it was in pretty good condition. Had a little bit of carbon build up dead center but nothing to cause any concern. no big lips on the cylinder and no wear or scratches(more on this later) Does have some extra carbon around and on the valve area of the head.

The really ugly part is that the piston is stiing down in the cyl .028-.035" and I need to know if this variance is good. It has worried me and I am going to check the cyl for any warpage etc. I only have a good set of calipers for measuring but I know that my measurements are not off by .007" maybe a couple thou but not that much.

Matts original "senior moment" about the stock gaskets was correct. When the last guy put it back together he used a stk 85mm head gasket, I am not sure how much trouble this could have caused as the dome inside the head looks about the same size anyhow. (should this be machined to match the sleeve??)

Oh and do not worry about those little springs and pins from the decompressor they just wash around with the oil in the head

The rings look and measure up fine and the cylinder was looking good except for a small section of scratches at the bottm of the cyl on the back (looks like a little bit of piston slap) I have not speced up the pin yet but there were no signs of wear or problems. This was a little suprising as the piston really looked good like it was only in use for a short time. Maybe I am just used to the auto stuff whre there wrecked.

My question is what do I do for a measurement to deck the cylinder. I have the cometic .025 head and .012 base. If I go to .010 off the cyl will it be too low with the shorter measurement on the cyl to piston. Help!!!!

04-02-2002, 07:43 PM
:confused: :huh

04-02-2002, 08:01 PM
Depending on where you take your measurements I would think there would be variations. I would measure above the wrist pin on both sides, they should be very close to the same. The piston to bore clearance will alter the readings at the front and rear of the dome depending on which way the piston is rocked in the bore. I would measure up the new piston and use the smallest measurement to base your deck height on.

04-02-2002, 08:20 PM
That would make sense and the "off" readings were on the front/back of the piston.

I only have these numbers as I am going to use the old piston. I am intending to change out the rings as long as I can get them before the weekend as I am having withdrawals from not getting out ridding:)

Does anyone have a opinion about fooling with the valves or not?? the quad and the head are only just over a year old and I was thinking of just "cleaning up" the exhaust valves in case there is any carbon building up. Should this be good?

And what about the amount to deck??? the most common measurement from the deck to the piston was .035, should I go with this?? (.035 -.020shaved= .015 = .025 cometic head gasket = .040 piston to head dim)

Just making sure I got this right before getting it cut down.

04-02-2002, 08:40 PM
As long as your piston to bore clearance is ok then use the old piston, otherwise best to tighten it up now while it's apart.
The numbers look good on the deck height you listed.
As far as the valves if your going to take them out of the head, check to see if the face is worn where it contacts the seat in the head. If they are I'd replace them with stainless, if not worn lap them back in and fill the chamber with water and look for leaks past the valve seats. If ok your good to go, retorque the head after some break-in time.

04-02-2002, 08:47 PM

You could think about using a high temp silicone for a base gasket. That should decrease the deck height by .010 - .011. I did that acouple weeks ago and haven't seen any problems even after a day of sand racing. :D

04-02-2002, 09:10 PM
I have not actually measured the bore clearence yet but will tommarrow. I think the valves held up good, and when I was cleaning them out (the exhaust chamber) they did not leak so I may reuse them as this is getting expensive and lots of stuff still coming (ex. suspension, pipes, axle etc)

I did no think about it before but any real boost to do some port work ??????


How do you like your set up?? Any real difference ??

I do have the .012 cometic which should still save me .008 and that should work fine, I hope :)

The mating surface on the base does not look perfect and I would be afraid of just using the chem bond stuff.

04-02-2002, 10:01 PM

My setup compared to stock is night and day. My friends keep telling me to leave it alone but I keep nitpicking- throttle response- power delivery- etc. I recently raced a modded banshee in the sand and got beat by 5- 10 lengths in 400-500 ft. Usually depended on my start because he had paddles and I didn't. I rode the banshee and it did have a touch more top end, maybe 3-4 mph. The Shee was ported, piped,carbed, and so on so I thought I did pretty well. It did seem to me that I had to hold 4th longer than normal and 5th seemed to take almost the whole 300-400 ft. to top out. Probably because I was playing catchup all the way! I'm running 92 octane gas and close to 11:1 comp so am wondering if a little better fuel would help? Just ordered a K&N air filter and removed the choke so maybe it will all add up. btw- didn't race any raptors or ds650s (they all left), but nothing stock even came close, even if they had paddles. Oh yea- my daughter kept getting beat by a warrior so I let her ride my 400- she started in 3rd and was at the finish when the warrior was only 3/4 down the track- AND SHE NEVER SHIFTED ONCE
Sorry about the book, hope this answers your questions? :D

04-02-2002, 10:15 PM
then you would say the all around cam worked well with your set up. It seems that you still have the bottom end "She beat the warrior in third gear and never shifted" but how is the mid to top.

I am intending on re assembling with the stock cam for comparison of the current mods and then add the cam in few weeks but still have not decided on which one.

Matt fischer had made a interesting rec of the web 479 as it should keep the bottom and help the mid and top a little also. I am still waiting to check out the wb cams but am sure they are just some one elses anyhow.

04-02-2002, 10:28 PM
I would guess that the type of riding you do would make the cam decision a little easier. I've got a stock bore and the wb all-around cam seems to have been a good choice. Great bottom and mid with a little better top end. I personally would go with a bigger cam than this on a 440 especially if you want top end.

Matt Fisher seems to have checked it all out and I would look for a cam in that range myself if I had a 440.

Matt Fisher
04-02-2002, 11:15 PM
Originally posted by 440EX4me
Well it is truely a J&E flat top piston in there and it was looking like it was in pretty good condition.

Interesting, I kinda thought the JE stuff would have a dome..

The really ugly part is that the piston is stiing down in the cyl .028-.035" and I need to know if this variance is good. It has worried me and I am going to check the cyl for any warpage etc. I only have a good set of calipers for measuring but I know that my measurements are not off by .007" maybe a couple thou but not that much.[/QUOTE]

powerslider had it correct- measure above the wrist pins.

Matts original "senior moment" about the stock gaskets was correct. When the last guy put it back together he used a stk 85mm head gasket, I am not sure how much trouble this could have caused as the dome inside the head looks about the same size anyhow. (should this be machined to match the sleeve??)[/QUOTE]

Oddly enough, when Patrick B was assembling his 440, he called GT Thunder twice about the stock gasket being in the cylinder- they said that's how they do it!:huh So is it a flattop or a dome? As long as nothing's been hitting, it probably didn't damage anything. Just use the correct 89mm gaskets when re-assembling.

The rings look and measure up fine and the cylinder was looking good except for a small section of scratches at the bottm of the cyl on the back (looks like a little bit of piston slap) I have not speced up the pin yet but there were no signs of wear or problems. This was a little suprising as the piston really looked good like it was only in use for a short time. Maybe I am just used to the auto stuff whre there wrecked.[/QUOTE]

Make certain that the cases aren't touching the sleeve. You may need to grind a bit to make certain there's clearance. When the steel sleeve expands, it can push on the aluminum cases, causing a hot spot at the bottom of the bore. Wala- additional wear or a broken piston (right, Patrick?).

My question is what do I do for a measurement to deck the cylinder. [/QUOTE]

You math in the other post looked good.

Matt Fisher
04-02-2002, 11:37 PM
Some interesting notes-

I looked at my Web 450/451 cam closely, and there's some minor wear on 3 lobes. The lobe closest to the sprocket has no wear, however.

I believe this is because the oil is slightly cooler there. This lends creadence to Mickey Dunlap's theory of rocker arm wear. Although I'm going to use a rather large cooler I already have, I will most certainly be utilizing his idea for getting cooler oil to the cam. An even better test will be on my friend's bike- he'll be using a Web 479 cam with heavier springs, and the original 1999 rocker arms.

My gut tells me that I'll be recommending his oil cooler frequently to 400EX pilots.

I got my cylinder back today, will take measurements soon regarding piston height, etc. No CR measurements for a week or so- I dropped the head off for port work. For some reason, I'm
guessing that I'll need to deck the cylinder just a bit and also shave the piston's top in order to get 11:1 with a squish of .040. I hope not, we'll see.

When both our bikes are finally together, I will have a comparison of the 450/451 vs. the 479 cam- everthing else on our motors will be the same.

440EX4me- I'm not sure who makes the WB all-around cam, but thier Track cam is the Web 450/451. Assuming you get a large enough cam, I'm betting you'll see a massive difference in power- maybe even more than when you went stock to 440. The 479 will not have as much bottom end as the WB all-around, but will have much more top-end. No free lunches out there. In any case, it'll be interesting to hear the results of the cam.

04-03-2002, 07:45 AM
Hey Matt.. Just for the record, my "off the shelf" JE 87mm piston is domed - VERY similarly to the Ross we got....

It's advertised as the 10.8:1 piston.

04-03-2002, 07:15 PM
Matt Fisher

I noticed the exact same wear pattern on my cam the other day, didn't think much about it. Now I'm seriously thinking about FSTs larger oil cooler. $ Thanks!

Matt Fisher
04-03-2002, 07:15 PM
Not at all a surprise since the same guy designed both of them.

Info for everyone else, I know you already are aware of it.

04-03-2002, 08:39 PM
Make certain that the cases aren't touching the sleeve. You may need to grind a bit to make certain there's clearance. When the steel sleeve expands, it can push on the aluminum cases, causing a hot spot at the bottom of the bore. Wala- additional wear or a broken piston (right, Patrick?).

Matt I have read this twice and for some reason I am just not getting it. Do you mean the top of the cyl???

Thanks as I do not want to screw it up now :)

04-03-2002, 08:50 PM
Oh and,

Just saved the cylinder before dropping it off to the machine shop today as I think I figured the squish wrong OOPS.

The orig cyl to deck was .035 + the OEM head gasket .040 total squish = .075.

The new cly to deck should be .027 (.035 -.008 w/ cometic .012 base v/s orig oem .020) + cometic head gasket .025 = .052 squish.

I was getting .020 shaved from the cylinder wow would that have been a bummer.

Now first let me that you guys agree with my math as I am getting crosseyed and second should I be decking off .010 or .012.

Also I should have this all back together on saturday and will let you know what happens.

04-03-2002, 09:43 PM
Hi,everybody....440EX4me the answer your ? about ..... "Make certain that the cases aren't touching the sleeve. You may need to grind a bit to make certain there's clearance. When the steel sleeve expands, it can push on the aluminum cases, causing a hot spot at the bottom of the bore. Wala- additional wear or a broken piston (right, Patrick?).

".....Is were the cylinder goes into the case's(bottom end) you might want to measure the roundness of the cace's.Because if it has a egg shape to it,or its to tight for the cylinder,when everthing heats's up and expands, it pushes in on the cylinder causing a tight spot for the piston,and also a hot spot(piston being to tight in the hole)...This can cause the piston to crack,so all you need to do is measure it and get like a air grinder and take out some of the material.....Hope this help's....Thank's.....

04-03-2002, 10:09 PM
OOOH OK I get it, was just stuck thinking about the top end:)


Matt Fisher
04-04-2002, 08:29 AM
With the base gasket on and the cylinder bolted down, the piston should be .015 in the hole. That plus the .025 head gasket will equal .040 of clearance from the piston's edge to the head.

I'd get enough shaved off to run a standard .020 base gasket and .025 head gasket. A standard fiber .020 base gasket should measure .018 after being compressed, btw. So if the piston's down .035 with a standard base gasket, then shaving .020 would bring it to .015. Add the .025 head gasket (the metal one's don't compress), and you have your .040 squish.

Then assemble everything and use a syringe to measure total combustion chamber volume and figure out your CR. If it's too high now, have the appropriate amount shaved off the top of the piston.

Fun, huh?:rolleyes:

04-08-2002, 09:18 PM
Well its all in there torqued down and even tested.

I ended up getting .012 shaved off the cylinder and with the cometic .012 base gasket ended up with .015(act. .010-.020) in the cyl. and everything seemed on track.

since I was working on the 400 at a friends garage and we had no syringe or other way to measure the chamber volume I thought hey why not just warm her up and put the compression tester to use.

Well sadly I must have missed something with the valves as the comp dropped to 75-78 psi. I had leak tested the valves and they held water but the exhaust originally did leak a little of the carb cleaner that my friend had tested with later. They did stop leaking after compressing the spring so I decided to have a go at it with the orig exh valves.

Anyhow the seat of the pants test was interesting. With the only mods not listed being some mild port work and cleaning up the oem headpipe the old gal performed pretty well considering all this work to lose some compression:D

The bottom end suffers a little bit and most likely due to the comp problem but the mid and top end somehow woke up. It did pull like never before from mid to top and this is puzzling.:confused:

I could short shift this thing constantly before and it would perform well but now it seems to want to see higher rpm for its power band. I do not mind the change and hope to get more bottom after getting the valve problem settled but does anyone have any idea why the change???????????

I am thinking the porting and opening up of the exhaust flow may be the ticket but I find I keep guessing wrong with this motor.

Also any ideas if the 479 web cam will help bring down the power band a little????????????


04-08-2002, 09:29 PM
I think maybe a valve is barely open or leaking. Those are really low numbers. Put some oil in there and see if your readings go up. Check vallve lash too. Maybe the rings havn't seated - did you check it before or after break in? Your seat of the pants improvement suggests maybe you have a faulty gage.

04-08-2002, 09:38 PM
Mike thanks for the quick reply

Maybe the rings havn't seated - did you check it before or after break in?
Checked it right after initial break in of approx 5 min run time. I will be checking again Tuesday.

Your seat of the pants improvement suggests maybe you have a faulty gage.
I had thought this also, it is a few years old and been through some use and abuse but appears to b ok.

Will the porting etc cause this much of a change. I have never done the porting with out the cam mods before and it just seems odd.

Matt Fisher
04-08-2002, 10:00 PM
I'm confused. Do you have an aftermarket cam in there right now? If so, which one?

Portwork is not going to drasticly change the powerband, unless someone really screwed it up.

Low compression will hurt low-end power more than top-end. Occasionally, you'll see guys lower the CR for full-race car motors to slightly improve the top-end, at the expense of low-end.

I would theorize that the better squish gave you more power, and you'll see even more once the compression is where it should be.

04-08-2002, 10:15 PM
Its the stock oem cam.

Port work was mostly exhaust port match up to gasket ID, de-burr casting marks and polish. intake de-burr and polish mostly.

Low compression will hurt low-end power more than top-end. Occasionally, you'll see guys lower the CR for full-race car motors to slightly improve the top-end, at the expense of low-end.

Matt this seems to make the most sense.

I am going to theorise that the low comp combined with the porting is most likely the scenario.

And now a point that I had failed to remember for the previous post.

It seems to be running a little lean as there is a more than occasional popping with deceleration. I am understanding that there is a 168 or 170 main jet in the carb now. I had also believed that 170 was the largest I had heard of for this carb is this true????

04-09-2002, 07:19 AM
Lean pop when "off the gas" usually is caused by an exhaust leak near the head or the idle mixture (screw or pilot /slow jet) is too lean. You'll need a #42 pilot jet in there for the 440. Try first just opening the idle mixture screw up 1/2 turn at a time to cure the lean pop. 170 is by far not the largest jet made for the stock carb. If you took out the cam, double check that it's timed correctly and not off a tooth. I wouldn't think it's a compression problem due to stack-up or piston choice, it's still got to be higher than stock. I'm sure you posted somewhere, but what piston and head gasket are you using?

Matt Fisher
04-09-2002, 08:00 AM
Light cleanup work won't do jack to change the powerband. It may add a smidge on the top-end, but won't move the effective power up or down any significant amount.

I'd say that the low compression combined with the lean jetting is killing your bottom end. Er, your bikes bottom end. ;)

I believe the same jets used in an FCR will work in the stock carb, and I'm positive that you can go at least to a 185. I've seen over 200's used in FCR's, so there's plenty of room to go.

The stock cam will offer the most bottom end. The 479 should offer more torque than the 450/451, but not like the stocker. The more mild the cam, the more bottom-end.

It's also possible that the cam's slightly retarded now due to the decking and thinner gaskets, but by only a degree or so. This would move the powerband up slightly, but only slightly.

04-09-2002, 08:34 PM
Lean pop when "off the gas" usually is caused by an exhaust leak near the head or the idle mixture (screw or pilot /slow jet) is too lean. You'll need a #42 pilot jet in there for the 440.

Mike that is what I was told is in there and never took the time to check if its a 42 or not. I will be checking the head pipe where it attaches to the head first.

Try first just opening the idle mixture screw up 1/2 turn at a time to cure the lean pop. 170 is by far not the largest jet made for the stock carb.

I was thinking of the idle mix tonight but left it alone as I was too busy, and would the bigger jets be avail from the normal sources say like K&N???

I'm sure you posted somewhere, but what piston and head gasket are you using?

J&E 11:1 piston w/ cometic .025 gasket also .012 base gasket and decked .012

And I am certain the cam is in the same as when disassembled.

04-09-2002, 10:20 PM
Light cleanup work won't do jack to change the powerband. It may add a smidge on the top-end, but won't move the effective power up or down any significant amount.

Maybe the exhaust was slightly more than light but the intake was very minimal.

I'd say that the low compression combined with the lean jetting is killing your bottom end. Er, your bikes bottom end. [QUOTE]

OK matt first I hope your winking at my four wheeled friend:)

Second this does make sense:o

[QUOTE]I believe the same jets used in an FCR will work in the stock carb, and I'm positive that you can go at least to a 185. I've seen over 200's used in FCR's, so there's plenty of room to go.

OK I still need some help with where to find the jets.

The stock cam will offer the most bottom end. The 479 should offer more torque than the 450/451, but not like the stocker. The more mild the cam, the more bottom-end.

Ok this is where I need to give some attention. I do like the boost to the mid and top as it gives the bike a good feel in these rpm ranges. It was way to bottom heavy before :D .

I am thinking to try the stock cam with a valve job first before doing any cam work to see if it works out better for my type of riding. (I am getting into some hare scrambles in the so I still want to keep the bottom end)

The change in the mid and top did feel like they would help out in the woods. I am hoping if I get the CR problem under controll it will boost the bottom enough to make me happy and let me move on to getting confused with suspension upgrades.

04-10-2002, 07:34 AM
I wouldn't switch cams any more than necessary to be on the safe side with the rockers. Every time you switch cams, and keep the same set of rockers, the rockers (and cam) have to wear in a little. The more times this happens the more chance you have of wearing through the thin chrome plating on the rockers. Definetly do a valve job though, if there is any question. When I took mine apart, after very minimal hours and no hard racing, the valves did need to be ground - probably needed it from day 1. Seats were OK, but I did them anyway. Don't forget to put some new valve seals in there. I think that your gage reading should be somewhere in the 130-150 PSI range with that piston/deck combo. Most any street bike shop has K&N jets, there's got to be a place local to you.

Matt Fisher
04-10-2002, 08:22 AM
Originally posted by 440EX4me
Ok this is where I need to give some attention. I do like the boost to the mid and top as it gives the bike a good feel in these rpm ranges. It was way to bottom heavy before :D .

Get the bike running properly first, then worry about more mods.

After looking at my cam and the way the 400Ex oils the cam, I'd strongly suggest FST's oil cooler, or your own version of it. I'm using a stacked design (like the stocker) with about 2x the stockers capacity. I do need to weld a bracket to the frame for mine, though. Between both coolers, I will feel much more confident about pushing it harder on hot days, and will also have reduced the chance for detonation.

04-10-2002, 09:42 AM
Thanks again for the input.

I think for now I am going to get the valves fixed up and see where we are then. I figure no sense (like Mike said) messing with a new cam now. I will wait till after I get it to make some comp before going any further with the engine.

Its gonna kill me to remove the head again and put the oem cam back but it just seems to make sense.

I am looking into the FST oil cooler after I finish this post. It seems like a very good "insurance policy".

And Matt I know what you mean by getting it running right first, but this suspension is seriously kicking my butt:) So i guess i think about it too much.

I will post the results after the valve work is done. This may take a little since I do not have a shop local that I have the confidence in and will need to find one.

Matt Fisher
04-10-2002, 07:33 PM
No reason to wait on the motor to do suspension work, they certainly aren't related. I meant don't bother with the cam until it's running properly. So we're all saying the same thing. :)

I would spend a few more hours on it, maybe the rings just need to seat better? Go back and double check the valve clearance. Is it possible you re-installed the rings incorrectly? If you have a burnt valve, it will often totally kill compression, not just lower it.

You should be able to get the cam in there by just pulling off the cam cover, not the whole head. It (the cover) has to came off to put the oil cooler on anyway.

04-10-2002, 10:02 PM
Matt Fisher No reason to wait on the motor to do suspension work, they certainly aren't related. I meant don't bother with the cam until it's running properly. So we're all saying the same thing.

I agree but I still do not need anything extra to be thinking about till this is done :)

I am hoping to have some time thur night to re set the valve lash so we will see what happens there.

You should be able to get the cam in there by just pulling off the cam cover, not the whole head. It (the cover) has to came off to put the oil cooler on anyway.

But I will need to pull the head if there is valve trouble to contend with. I do believe this is the problem but who knows for sure.

How does the FSt oil cooler plumb into the system???

Matt Fisher
04-10-2002, 10:36 PM
Here's the stock cam oiling system. Look at the oil filter cover. There's a oil galley that travels up at about the 10 o'clock mark through the case cover. It goes to the base of the cylinder. You'll see an oil line cast into the side of the cylinder, the oil travels up from there to the cam. The sprocket side of the cam has a sealed bearing. The oil travels up the galley in the cylinder, fills the "pocket" created by the sealed bearing, and gets forced through the cam itself. It comes out of holes in the cam itself, and gravity feeds back down the cam chain area.

The FST cooler intercepts the oil before it gets to the cylinder. The side cover is tapped into the oil galley, and the line giong to the cylinder is plugged, forcing the oil to go into the cooler. After being cooled, it goes into the cam cover, where another hole has been tapped. Because the "pocket" fills up with oil just like the OEM system, the only difference is it's cooler oil.

Given the conversations I've had with Megacycle cams, Web cams, and after examining my cam, I really believe that cooling the oil before it hits the cam is a really good idea. I won't be using the FST cooler, as I have a much better one, but I'm in total support of the concept.

04-15-2002, 12:00 PM
Figured it was time to get this thread up on the front lines again!

Some additions. I slapped on a FCR41 this weekend. Like Gabe(?) reported, incredible bottom end increase w/lightning quick response. I'm amazed at the difference over the stock carb (w/o a choke). Even with the GTT cam, the bottom end hit is way more than bone stock, very noticeable mid increase and top, well I didn't have a long enough area to really stretch it out - yet. It completes the whole 440 & cam combo. There's now more of a difference between my modded 400 and a stock one, than my wifes 250EX and a stock 400. Took the better part of a day to sort out the jetting, but it was well worth it. Dollar for dollar probably the best motor investment yet.

04-15-2002, 12:59 PM
Mike thats a great sounding increase with the carb and I am glad someone here got their 440 running right.

I did not even start to think of the carb yet.

Did you notice any changes with starting??

04-15-2002, 02:19 PM
Personally, mine starts easier with the FCR, even though it does not have a choke.

Sometimes when it's really cold, sub 20 deg, it will lean out pretty badly until you get a little heat built up, but if that's the case, you really shouldn't be putting the engine under load until it warms up anyhow.

That would also probably be easy to correct with cold weather jetting, but I don't really ride when it's that cold anyhow, so I don't generally bother.

As Mike said, the throttle response with the FCR is unreal - I've actually geared my quad up to tone down the response for cross country racing since it was causing steering problems coming out of corners & if you accidentially bump the throttle a little when going thru a rough section, you get a serious unexpected surge of power...

Expect some tuning time, but once you get it dialed in, it's a great carb.

04-15-2002, 03:44 PM
Mine also starts up much easier than it ever has. The carb tunes, acts, and seems to be designed, similar to the Webers on my race car (at least something is familiar for once). Yes, Gabe, I know there's more fine tuning to go - but the results so far are MUCH better than expected.:D :D :D

04-15-2002, 04:32 PM
Yep, I've still got some fine tuning to do on mine as well... But it runs well enough that it's not really a priority at this time. Just a couple little weird areas that could use a little time spent on them.

04-15-2002, 09:16 PM
The FCR sounds like a great swap for the stocker hmmmm I guess there goes another $300.00-500.00, but I will not be getting into anything new untill I get this compression problem fixed.

I had talked to some local machine shops and even a shop that deals with bikes and quads and I looked like I was gonna be out another 100.00 for the valve job.

I have a friend that claims he has doen this many many times and from what it sounds like he is just doing a modified version of lapping the valves. I guess he is using lapping compound and basicaly just putting it between the valve and seat and then turning the valve by the stem with some sort of drill or whatever.
Does this sound like a good idea?? He claims it sets the valve and seat at the same time unless the valve is bent or bad and then would need a true valve job. HELP

I wan to get this right thew first time so I do not have to invest another 28.00 for the cometic 0.025 head gasket two more times if its wrong.


Gabe did you ever get any testing done on the shocks or the measurements and numbers for the carrier info??

04-15-2002, 09:21 PM
Still waiting on my PEP shocks.... I've got the dual row carrier info written down, I'll try to find it tonight, hope I haven't lost it.

04-15-2002, 09:42 PM
Thats a reallllllllll longgggg wait, hope they perform as good as it is long to get them.

Matt Fisher
04-15-2002, 10:04 PM
Did some measurements on Saturday. I show 38cc's for the head, and with a .020 base, .025 steel head, and the domed Ross piston, 39cc's. The good news is that that equates to a 11.28 compression ratio. The bad news is that without the head gasket, the squish is about .045, with it I end up with .070- yuck.

With the head gasket removed, I had a 35cc area, equating to a 12.57 CR. This tells me that the cylinder will need to be decked the same basic amount as a flat top Wiseco, but then I will need to remove material from the chamber by unshrouding the valves and/or shaving the piston top. Arrrugh. The good part of doing either of these is I'll get more power from the chamber work, and a lighter piston after it's machined.

I'm betting the JE pistons are a mirror image of the Ross ones, and they will have the same issue of squish vs. compression ratio. Has anyone checked the squish of a 416 piston, I'm very curious as to what they end up with.

The Ross piston delivers what was promised- a 11.2 CR. Too bad there's the squish issue.

440ex4me- you can go to Sears and get the valve lapping compound plus a tool for doing it by hand. The tool is a stick with a suction cup on the end. Pull off the springs, put some lapping compound on the seat, and use your hands to spin the valve back and forth. We used to do that in 4H with lawnmower engines. Cheap- but a 1 angle valve job sucks for performance. I'd do it but re-use the exisiting head gasket. If it fixes the problem, have a real valve job done, and then slap a new head gasket on there.

Good to hear about the FCR working so well- that's on the list...

04-15-2002, 10:18 PM
Matt, did you see Lazarus' post on the e-mail list about the deck height issue?

From what he was saying, I'd say the "off the shelf" JE is probably the same.

Another interesting note is that he mentioned that with a custom piston with a lowered pin height (to correct the deck issues), he noticed about a 1hp gain on the dyno - he did not note, however if that was peak or across the board...

He also noted that someone who doesn't plan to tear down and freshen up every so often should probalby live with the lower deck height.

Has anyone considered how much decking the cylinder and/or switching base gaskets will affect the timing? I know it can be corrected with an adjustable upper sprocket, but then I'm thinking slop, especially as the chain becomes worn, on top of essentially being "too long".

I know as my original chain became worn out, it threw a ton of retard into the cam timing - I didn't actually measure how many degrees, but it was enough that when I replaced the chain it altered my jetting significantly. That was after one season of heavy riding on a mostly stock engine with mostly synthetic oil....

Lazarus has also mentioned to me in the past that of the engines he's built, the guys running synthetic seem to be getting longer cam chain life.....

Matt Fisher
04-16-2002, 08:30 AM
No, I hadn't seen that post. I end up spending more time here, because 70% of the time I click on a post, all I get is some damn advertisement from Yahoo. Since my download speed is slow, it ends up taking forever to go through stuff. I can wade through the silly posts by 13 year olds over here pretty quick. I'll have to go searching for that post though. I figure Laz has forgotten more about building motors than I currently know about them...

The other reason I'm worrying about the deck height issue so much is a small squish will create lots of turbulance, and reduce the chance of detonation. At 11:1 or so, I'll need all the help I can get with Calif's 91 octane pump piss.

I'm considering getting a degree wheel and slotting the cam gear, but have no ideas on fixing the longer chain issue.

It's really frustrating that none of the pistons are "correct" out of the box.:mad:

04-16-2002, 09:18 AM
Yeah, I just get e-mail downloads, so I don't have to put up with the ads (which have gotten bad lately if you use the web based portion) - I just have a filter setup to automatically dump them into their own folder in my e-mail proggy so they don't clog up my inbox.... I feel your pain on the slow dialup - heck I work for the phone company and can only get 28.8 dialup from home.

Do you ride sand much?

If so, you may want to be really careful. On our last trip to the dunes one of the guys from the list had a 416 JE off the shelf piston (probably ending up with around 10.6:1) - he was detonating with premium unleaded. Granted he is running the XR cam, he may have been ok had he been running a more aggressive cam.

We ended up having to use a race gas mix in his quad - problem solved.

If you don't have any race fuel distributors in your area, why don't you just order in a 55gal drum & mix it 50/50 to be safe? Race gas has a very long shelf life if stored properly. A 55gal drum would last a very long time running a 50/50 or 30/70 mix for the quad.

I think most of the "off the shelf" pistons are setup to cater to the guy that's going to drop the piston in and forget it, allowing carbon buildup, wrong head gasket sizes (guilty myself - since it doesn't matter with the deck height issue), etc....

Matt Fisher
04-16-2002, 06:30 PM
No too much sand, although that may change once everything is put together. I'll either bring some Touline or race fuel when the temps are high, add as needed.

The whole idea behind going with the 440 was to get rid of my current 12.5:1 stock bore, but not loose any power. $4.50 a gallon gets old real quick. It'll really irritate me if race fuel is needed on a regular basis. For someone that doesn't mind running race fuel, a high CR piston is a great way to go.

I'll run a bit of water through the motor every now and then, the steam does a great job of cleaning off carbon, or I'll just use some of the off-the-shelf products...

04-16-2002, 08:11 PM
Matt, be very careful with tolulene. It's extremely poisonous and can be absorbed through the skin! Also can cause permanent eye damage if splashed in the eyes.

04-16-2002, 08:26 PM
Hey Matt,I'v been meaning to call you but just havent had time.Anyhow I got a new Dennis Kirk mag,and in it it has a degree wheel ket in it,$123.99 ouch!! it's a Hot Cams set up. It also has a cam sprocket's for Honda's,it has a bunch of holes in it to adj. the cam timeing,but nothing listed for the 400,so i dunno? It's made by Parts Unlimited,i'v never herd of either one of these's??

I also did a C.R. test on my 440,with the wisco i have in it right now,it came out to right about 98 PSI perty sick huu???...lol....my friends bone stock 400 had 118 i think. And my ,manual says it should have around 110 to 128 I think?So other then that nothing else,I haven't had time to get started on my yet so..


04-16-2002, 08:39 PM
...O yeah Matt I almost forgot,rember when we were talking about stroking it..LOL...:eek: ..lol...the crank......lol...Well i found that mag that had it,Built by LRD 13;1 wisco with a 4mm stroke,makeing it a 460cc,The third and fourth gears had to be ground for clearance..lol....

Matt Fisher
04-16-2002, 09:08 PM
Patrick, I don't see why any automotive degree wheel won't work. If I need to move the cam, I'll probably just slot the gear.

98psi does seem low, but 440ex4me has you beat.

The Ross piston will bring that PSI number up. When are you going to be done with the tractor work, you've got to be itching to go riding...

I still don't get how the gears are ground for clearance. Making them smaller would weaken them, plus they wouldn't mesh properly. :confused:

04-16-2002, 09:28 PM
98psi does seem low, but 440ex4me has you beat.

Now thats not the competition I was looking to win :o

04-16-2002, 09:29 PM
I still have about a month left,I ride a little bit but only on sunday,my only day off,:( Yeah thats what the mag. said it's in ATV Sport,April 2002..so...But yea know what your saying,you would think they would not work to well,for to long....

04-22-2002, 11:32 PM
Now for the valves.

I had some time today and looked into the getting the valve issue fixed.

It seems that there is some debate between just lapping them or doing a complete valve job. Does anyone have any ideas here?

I was also told that the valves themselves are sort of a weak point. Is this true?

Also that many atv valves are the run of the mill 3 piece design and that even some of the stainless ones are also. Is it worth the effort or $$ for the stainless, what benefits and where to find them??


Matt Fisher
04-23-2002, 12:22 AM
Did you decide that the valves were the source of the low compression readings?

If that hasn't been determined yet, I'd just lap the suckers to make sure they're sealing before sinking any real money into them. Heck, I'd re-use the head gasket. $20 and 3 hours of time, tops. If that fixes it, then spend some cash to do it right.

Are the stainless ones better? Sure they are, 1 piece valves are less likely to have the head break off and bounce around in the cylinder until they jam against the head and piston, causing the motor to stop instantly. Bent con-rod for sure, destroyed cylinder and piston, possible stripped gearbox, maybe even cracked cases from the energy of the crank also being halted like a Yugo into a bridge abutment. Let's not think about what happens to you if it does this while your're in mid-air over a trickey double with a set of whoops directly after, and a whole pack of slightly crazed, adreniline juiced quad riders right behind you...:devil

Course', I'm not bothering to change mine, so I wouldn't worry about it toooo much. :blah

Matt Fisher
04-23-2002, 01:06 AM
Well, I took all the information I gathered, plugged it into this site http://www.kb-silvolite.com/ and came up with this: My current CR with the Ross piston is indeed 11.28:1, and if I deck the cylinder so the piston is .015 in the hole (.040 squish with the head gasket), then I need to remove 6cc's of material from the head and piston to get it down to 11.1:1. I'm guessing removal of 2cc's with valve unshrouding, and then 4cc's from the piston's dome, which is 10.599cc's as delivered from Ross. What a PITA! I'm also going to order a degree wheel just to see how much off the cam's timing really is, although I know it really won't be much. I will also be able to see how much an old timing chain affects it.

Arrugh, I'm gonna' eat my socks if some damn 416 comes anywhere near me in a drag race. I keep thinking I should have just bought a c-dale.:rolleyes:

The http://www.kb-silvolite.com/ is a pretty cool site. Spent a while there, it's really easy to manipulate CR on our little motors. Just a very small amount of clearance makes a significant difference.

I went and visited the coating guy today, and my cam, rockers, valves, cam cover, cylinder head, piston, and new WB headpipe will all be getting different kinds of coatings that are designed to manage the motor's heat better. Combined with my big oil cooler, fixing the above mentioned squish issues, I'm really hedging my cards to make sure it doesn't detonate with 11.1:1 running 91 pump gas (Calif's crap). In the sand. In 100+ degree heat.

I also went down and picked up a rattle-can of paint to match the OEM frame color. I figured after welding in gussets, I may as well make it close to the factory color. Might even squirt a coat on the a-arms to cover the rust spots...

04-23-2002, 06:37 AM
Matt, I'm curious what coatings were suggested for the cam and rockers? The other parts I know, but there has been much discussion and some testing done on cams and rockers - most with negligible to detrimental results. Remember on your TBC's for the piston/head, if you reflect heat back into the combustion area, you will generally need a higher octane fuel. Are the coatings paint or plasma types?

Matt Fisher
04-23-2002, 08:07 AM
Although I stood there and BS'd with the guy for over an hour, I couldn't tell you the specifics of what coatings are to be used. The header gets ceramicoat, shiny stuff. The cam cover and head will get some kind of flat black super heat rejecting coating, while the piston's top and valves get a reflective coating. He said that the heat gets absorbed into the head, not the piston or valves. Now that you mention it, that would make for a smaller heat sink; I'll have to talk with him about that.

The cam and rockers get some kind of slippery coating, and I believe everything is the paint on variety. Without knowing of the 400EX's propensity of eating performance cams/rockers, he was joking around about a friend of his in AZ that road races MG's. As well as the pathetic Lucas electronics, MG's are known for having lousey oiling systems. Lovely choice in race-cars. :rolleyes: He'd get about 3/4 of the way through a race, and the top half of the motor would grenade. The cam would go first, killing the rockers, but the mains would stay oiled. Hadn't finished a race yet. He had his friend ship him the cam/rockers, and when the next race came along, it finished. The top-end still ran out of oil at the 3/4 mark, but the cam and rockers were unharmed. He ran the remainder of the season with no failures. His friend now sends the coating guy 20 cam and rocker combo's a month for other MG racers.

I wonder how a coating could be detrimental to the cam/rockers? Any suggestions?

04-23-2002, 10:15 AM
The cylinder (fins) would also make a good candidate for the "super heat rejecting" coating. That's the one I'd like some info on.

A solid film lubricant, high metal content w/moly disulfide would work well on the cam. I would be very hesitant to put anything on the rocker pads for the following reason. In order for the coating to stay on the base metal w/o flaking off, the base (rocker pads) must be carefully prepared. This is done by vapor degreasing (~192 deg. F. - no big deal), then grit blasting with something like 120 mesh Al2O3, followed by the lubricant application.
The grit blasting, which is necessary for adhesion,will remove, lift and/or blister the thin chrome plating on the rockers. As you can imagine, that's not a good thing. I would just stick with coating on the cam only. BTW, MG rockers are not chrome plated so it would benefit them.
The lubricant on the cam must be one that is designed to work in a wet environment with oil. Many/most don't "get along together" because the coating doesn't let the oil film stay on the part.
E/M Corporation Lube-Lok #4253 is just what you want for the cam. They have facilities in Mountain View and North Hollywood CA. If you'd like I'll email you their brochure - hope you have a cable/DSL connection though!

Matt Fisher
04-23-2002, 09:16 PM
Gee, doesn't sound like you know anything about coatings, do you?:rolleyes: Great information from ya' Mike, as usual. I think I'll print that ditty out and show it to the coating guy, I'll also get some info on the heat rejecting stuff.

These damn factory Honda rockers are really beginning to irk me. I really think Honda could have done better. I sat down with my neighbor and started dialogue about making roller rockers for the 400EX. A bit of a shot in the dark, but I don't see why it wouldn't work. The concept of being able to run much more agressive cam profiles is very appealing, as well as having a reduction in friction. Anybody else like the idea of roller rockers?

No, I have anything but a fast connection. Takes quite some time to download pictures. Makes buying a magazine almost worthwhile.:D

My machinist feels that removing 6cc's from the combustion chamber with unshrouding and re-shaping the chamber should be possible. Maybe I won't need to shave the piston after all.

04-23-2002, 09:30 PM
These damn factory Honda rockers are really beginning to irk me. I really think Honda could have done better. I sat down with my neighbor and started dialogue about making roller rockers for the 400EX. A bit of a shot in the dark, but I don't see why it wouldn't work. The concept of being able to run much more agressive cam profiles is very appealing, as well as having a reduction in friction. Anybody else like the idea of roller rockers?

Matt check your pm's.

I think it would work great and solve some problems and should not be all that more ($$) than the hard facing cr@p once in production.

The info I need to get going on this is the estimated load for the rollers. I need get the spring pressure and estimated gain or loss from the leverage of the rockers. Does anyone have any of this info?????

Cam speed in rpm wouldnt hurt either


04-24-2002, 08:09 PM
If you build it they will buy it, I would very much like to see roller rockers to cure once and for all these un-necessary problems.
The cam rpm is half the crank rpm. Light material rollers running on needle bearings would be the ticket.

04-24-2002, 10:58 PM
Not sure about spring pressures but would be surprised if the stockers were more than 250 psi at .400. They don't feel to strong when installing them.

I think roller rockers would be totally cool, although I suspect that the loading problems with the stock rockers would be transfered to the subrocker assembly and slipper surfaces when much more agressive ramp profiles are used.

I don't have any answers, just questions. :confused:

04-24-2002, 11:51 PM
Got questions??

Well lets here the good ones:D

Cant be any worse then mine:cool:

04-25-2002, 11:36 PM
Compression Ratios

I remeasured mine the other day and this is what I found:
Stock Bore - JE 10.5:1 Piston

Combustion Chamber - - - - - - - - - - - - - - 38cc
XR Head Gasket .025 - - - - - - - - - - - - - - 3.6cc
Deck Height .007 (no base gasket) - - - - 1cc
Piston Dome minus Valve Reliefs - - - - - - (3.7cc)

Total Combustion Area ----------------------- 38.9cc
Swept Area ------------------------------------- 397cc

(38.9 + 397)/38.9 = 11.20CR

However the Quench area is only .032
So if I put on a cometic base gasket .012 thickness it will add 1.7 cc, drop the CR to 10.78 and give a quench of .044

If I use the stock base gasket .020 thickness, it will add 2.9cc drop the CR to 10.49 but make a dismal quench of .052

I think I'll get the Cometic base gasket and be ready to ride!
Hope this is of interest. BTW - these #s won't be the same for big bore kits. :D

11-12-2002, 07:51 PM
An update on the numbers for my 440 problems. I had found a couple of calculators (thanks Matt Fisher) online and recently found all the info I needed to get the numbers right.

Below is the original JE/IMS set up that was in the quad when I had purchased it. It ended up being an 88.5mm flat top JE and had the OEM base and head gaskets. The deck height may have been more but I am not sure if it was later decked .020 or .022 so the comp may have been even lower.

Orig 440 set up.

Bore in 3.4843
Stroke in 2.7559
Head cc's 38
Gasket Thickness in 0.035
Deck Height in .032
Dish or Valve Pocket [-] or Dome [+] cc's 1cc
Number of Cylinders 1

Displacement Cubic Inches 26.28
Compression Ratio 9.7:1

same piston/ sleeve after decking and cometic gaskets (.025 head - .012 base) Note: comp never realized due to poor valve job and wrong rings (this would have most likely been acceptable if it held the comp).

Bore in 3.4843
Stroke in 2.7559
Head cc's 38
Gasket Thickness in 0.025
Deck Height in .004
Dish or Valve Pocket [-] or Dome [+] cc's 1cc
Number of Cylinders 1

Displacement Cubic Inches 26.28
Compression Ratio 10.89:1

Current project using Ross 89mm dome top piston and prev decked cylinder and rebored and honed sleeve etc.

Bore in 3.508
Stroke in 2.7559
Head cc's 38
Gasket Thickness in 0.025
Deck Height in .010
Dish or Valve Pocket [-] or Dome [+] cc's 8.6
Number of Cylinders 1

Displacement Cubic Inches 26.64
Compression Ratio 13.49:1

I was thinking that this may be too much comp for the stock rod and bottom end so I was thinking to go back to the stock base gasket (.020 v/s .012) which would add .008 to the deck height and then the results were:

Bore in 3.508
Stroke in 2.7559
Head cc's 38
Gasket Thickness in 0.025
Deck Height in .018
Dish or Valve Pocket [-] or Dome [+] cc's 8.6
Number of Cylinders 1

Displacement Cubic Inches 26.64
Compression Ratio 13.04:1

Now I only need to figure out the squish. Any ideas etc.?

PS I chose to post in this thread since it is hands down the best one I have seen on this subject ever, and wanted to bring it back to the top again.

11-12-2002, 08:09 PM
Looks like your building a bomb lol. There is no way I would attempt to run 13:1 comp ratio in this motor, you think you've had problems before. It will grenade in short order with the stock lower end.

From your deck and head gasket #s your squish is .043. Cut the piston dome to lower the comp ratio.

A 39.5cc chamber volume will yield 12:1 comp ratio with 435cc cyl volume.

11-12-2002, 09:47 PM
I would like to leave machining the piston as a last resort.

What about running the Honda OEM head gasket?
I listed it at .035 but was told it may be .040 so that should bring it under 13:1 (12.7:1 approx) and that should be ok, but what would that do to the squish?

Any other ideas?

11-12-2002, 10:05 PM
.048 squish with the thicker headgasket, You better change the rod if your bent on running the high comp ratio, it's life will be short if you run the motor hard then you'll be back at square one again with big bucks in parts. I wouldn't take the chance but it's your call.

11-12-2002, 10:17 PM
So you think even with the stk thk head gasket I would be over stressing the bottom end?

Could be a incentive to go for the stroker over the winter :D but I think I could do without the quad being down again too.

What is a good comp limit for the stk bottom end?

Matt Fisher
11-12-2002, 10:34 PM
I'd have to say that a 13:1 would flat rip. I'm also going to go out on a limb and say that if you keep the stock rev limit that you'll be less likely to have a failure than running 11:1 with a rev box. If you're feeling lucky, the 13.5:1 with .035 squish combo would be lots of fun. Wheeee...
There's got to be some kind of smilie character for that combo...

On the other hand, a rod would be great insurance...

Also, did you get the special lightweight alloy wrist pin from Honda Jim?

FYI- on my motor, I ended up milling some of the piston dome off, plus cutting 2cc's out of the head to get my CR where I wanted it- 11:1 with a squish of .040

11-12-2002, 10:34 PM
not that it matters but, i ran my 425 13:1 for a long time with no troubles, untill i my sleeve just deterioated. I belive it merely hearsay what people say about it being dangerous for 13:1 compression. But JE says its better to run teh flat top pistons. So I dont belive you should run more than 12.5 compression.

Matt Fisher
11-12-2002, 10:59 PM
The stock head gasket won't work properly- It'll hang off into the cylinder due to it's having an 85mm hole while you now having an 89mm cylinder. Cometic would be happy to whip up whatever thickness gasket you need, btw.

You could use the stock base gasket, I believe they do fit. Don't they?

X-rider's correct in that there's no way to know for sure if you're overstressing the lower end or not. It might grenade with an 11:1, or might run like a naked man from Richard Simmons (read: fast and forever) with the 13.5:1. A better rod just makes it less likely to blow (no relation to Mr Simmons).

At the elevated CR's, make damn sure you aren't detonating. That will insure your motor ends up looking like a pile of smoldering aluminum.

In theory a flat-top piston is better than a domed one. It provides for a better, faster flame front; which is more detonation resistant. In practice, the dome's we're dealing with are quite small, and not having them usually results in the CR being too low. No one seems to make a flat-top piston with a higher pin to top height.

Now a stronger rod that was about .040 longer than stock would be really cool...

11-12-2002, 11:07 PM
Ok I am thinking about adding the a stk base gasket (doubling up with the cometic .012) changing the deck to .030 and expecting the following.

Cylinder Head Volume (cc) 38
Cylinder Head Vol (cubic in.) 02.318
Piston Head Volume (cc) -8.6
Piston Head Vol (cubic in.) -0.525
Gasket Thickness (in.) .025
Swept Volume (cubic in.) 26.637
Gasket Bore (in.) 3.508
T.D.C. Volume (cubic in.) 02.325
Cylinder Bore Diameter (in.) 3.508
Gasket Volume (cubic in.) 00.242
Deck Clearance (in.) .030
Note: Neg. nubmer above deck, Pos. number below deck Deck Volume (cubic in.) 00.290
Stroke (in.) 2.756

Comp 12.47:1

Now how about the squish on this one?

11-13-2002, 09:01 AM
Well, I just spent the better part of an hour reading through this thread in its entirety. There is an amazing, and frankly overwhelming, amount of information.

Based upon the collective information gathered by the main posters in this thread is it possible to come to a collective recommendation for the average user who is looking for the best piston combination ( I don't even want to throw cams or carbs into the mix).

Based upon the people I talk to and the majority of the threads on this board, most people who mod their 400's are wanting a 416 piston and are looking for a reliable increase in power without using race gas and without having to do any decking. Based on that, can we get a recommendation on the following:

Manufacturer: (JE, Ross, etc)
Compression ratio:
Flat topped or domed:
Any other custom piston recommendations (i.e. reduced weight, custom wrist pin, etc):
Recommended base gasket:
Recommended head gasket:
Other info:

Or is there already a kit out there that provides a reasonable and accurate compression ratio, with a relatively flat topped piston (which apparently give better performance than those that are more domed), and the appropriate head and base gasket combo to get us to the magical squish area (or is it quench?) of .040?

If possible, it would be nice to get the same info for a 440 kit as well.

Maybe I'm hoping for too much, but I figure it's at least worth asking.



11-13-2002, 10:39 AM
Dennis (damn was I hoping it was Duncan :rolleyes: )

good thought but every time I have tried to get anything with a mod on this quad to be simple it just doesnt happen.

One of the main reasons I resurected this thread instead of starting a new one was that there is so much excelent info here anyone could determine how to properly set up their existing or future piston no matter which size or MFG it is.

And it also shows why a properly preped 416 motor could out pull a 440 and then get completely left in the dust by another.

And though you could almost say that the info I have posted on my experience will give you a basic guide on what to expect from both the pistons I have used there are still some variables that will require things to be assembled and measured before you can answer your questions.

The diff in design and compression etc between the 11:1 flat top J&E (it could have been 10.8:1 also?) and the 11.2:1 Ross dome top are pretty big and both require diff mods to work right. And this can also change motor to motor.

I am just glad that I had the chance to get this info in the first place and that there were other members who had this knowledge to share.

Its looking like I am going to try the dbl base gaskets .012 and .020 and shoot for the 12.4:1 comp as posted above, wish me luck :) and any idea on squish (damn I am gonna have to find how to figure the squish and stop being a pain in the arse)

11-13-2002, 11:00 AM
Without over complicating it, squish = head gasket thickness + deck height. In other words, if the gasket is .025 thk. compressed and the piston is .020" "in the hole" at TDC, the "squish" would be .025 + .020 = .045". If the piston were .005 out of the hole (negative deck height) then it would be .025 + (-.005) = .020".

11-13-2002, 11:12 AM
thanks Mike.

Hmmmm then I am getting a little high on the squish with that dbl gasket set up.

I am not thinking thats good with the dome top and higher comp. Damn this is never gonna end LOL

11-13-2002, 11:30 AM
That's why I suggested you modify the piston so all else can remain the same, that is what I would do in your case....

11-13-2002, 11:41 AM
That's why I suggested you modify the piston so all else can remain the same, I am deff looking into it, thanks.

11-13-2002, 02:00 PM
this is the best thread I have read so much usable info, I am currently having the 440 wiseco bore Kit intstalled and now think I am going to have my cylinder decked by .010-.012 and am going to use a thinner cometic base gasket and head gasket getting me closer to the 11/1 compression ratio ? thinking I will be in the 10.5/1 range with these mods,please correct me if I am wrong .Will I be able to run super unleaded gas? I do not want to run race fuel.fyi has stock cam , Joe

11-13-2002, 08:13 PM
is there a set standard on squish? Is there clearances that are too close? Also if squish is deck height + compressed head gasket width then quench is distance from piston to top of dome? And if it is, how would you measure quench? Measure the dome distance to the head mating surface and then add that distance to your squish?

Matt Fisher
11-13-2002, 09:03 PM
As much as I'd like to say "here are the best combo's to use", that ain't gonna happen.

When I first started looking for a 440 piston, my primary concerns were weight and compression.

Due to the fallacy that a 406/416 will outperform a 440 due to piston weight, I made that my first priority. JE was less than helpful, while Honda Jim at Ross was able to come up with some very good info (also on the JE's since he designed their piston too). BTW, there isn't a real significant difference in weight between the OEM piston assembly and any of the aftermarket ones, and it's possible to make them equal.

Not only was the Ross a couple grams lighter than the JE, but they also had special lightweight alloy wrist pin available. Additionally, they offer a service to mill the piston for additional weight reduction. Yes, I did both, although I needed to purchase 4 pistons for them to do the milling.

As a side note: My seemingly anal fixation over a few grams really is quite silly given how little a gram weighs. Hold a dollar bill in your hand. That's a gram. Not much huh?

I struggled with the Wiseco due to knowing that their pistons often were coming up short in the CR dept (see the info posted by Mickey Dunlap). Being a flat-top piston, that made sense. The key, however, is in the piston to pin height. A flat-top can easily have the same/more compression than a domed one, if it's height is greater to begin with.

The problem I ran into was when I decided to set the squish. That's the distance between the outer edge of the piston and the head, when the piston's at TDC. A smaller squish will create turbulence, which increases power and reduces the chances of detonation. If it gets too small, the piston can hit the head at high RPM's :eek:, and gets very sensitive to carbon build-up (.040 isn't much space).

However, as you decrease this distance, you cause the compression ratio to increase. This was a problem for me because I didn't want to run race fuel, so I needed to keep the CR to about 11:1.

I ended up milling a bit off the piston's dome, as well as unshrouding the valves, which resulted in a 2-3cc larger combustion chamber (I did 2 motors). After all that milling, cutting, measuring, cussing, etc., I'd bet that if I'd just assembled the bugger with the 11.3:1 piston from Ross I'd only lost out on about 3 hp.

My suggestion- if you have the time and patience to "do it right", then by all means- go for it. If not, I'd suggest 2 options for a pump gas motor. 1) Pick up a Ross piston (and spend an extra $20 on the lightweight alloy wrist pin), drop it in there, and go have fun. 2) Get a Wiseco piston (I think www.thumper-racing.net has specially milled ones), and then mill about .020 off the cylinder to up the CR.

If you going to run race fuel, then don't leave power on the table. Run the same Ross piston, but mill about .020 off the cylinder. You'll end up with about a 12:1 motor.

A couple of tips-
-I wouldn't even consider using the stock cam with a 440, and the XR is also too small, IMO (ok, maybe for a tractor motor). Try a Web 450/451, or the Web 479 with some Kibblewhite valve springs.
-Mickey Dunlap's oil cooler is a killer idea. I used his basic design, then made up my own custom cooler. But for the limited amount of money he wants, it's a no-brainer. Especially when you consider that (according to him) hardfacing the rockers is unnecessary when using his design.
-These websites may help in figuring out compression ratio's- http://www.rosspistons.com and http://www.kb-silvolite.com
-The stock squish is about .085+/-

11-13-2002, 10:04 PM
This post just keeps getting better. Great info guys.:)

11-14-2002, 03:15 AM
Ok I decided to assemble earlier tonight and since all I was able to get quickly was the stock .020 base gasket I am now looking at a comp of just under 12.5:1. I have been told that the stock rod and bottom end should hold up with the stock rev limiter, I guess we will see.

The only thing I am a little confused about is the above info on measureing squish and how a dome top piston would effect that info. I cant believe that I could be getting 12.5:1 with a squish of 55 is this right? I am also considering having the dome reduced and getting the lighter piston pin and lightening the piston when its real cold here in Jan and Feb so this may be temporary if it doesnt really kick.

Well there is still some final assemby and set up to be done and I hope to get to break it in late on friday and will post what happens etc.

Well here is the final info:

Cylinder Head Volume (cc)38.000
Cylinder Head Vol (cubic in.) 02.318
Piston Head Volume (cc)-8.600
Piston Head Vol (cubic in.) -0.525
Gasket Thickness (in.)00.025
Swept Volume (cubic in.) 26.637
Gasket Bore (in.) 03.508
T.D.C. Volume (cubic in.) 02.325
Cylinder Bore Diameter (in.)03.508
Gasket Volume (cubic in.) 00.242
Deck Clearance (in.) .030
Note: Neg. nubmer above deck, Pos. number below deck Deck Volume (cubic in.) 00.290
Stroke (in.) 02.756

11-14-2002, 07:58 AM
Thanks for the replies, gents. I was hoping that maybe Ross or JE would have updated their pistons to reflect the information that you guys have assembled.

Matt, thanks for the recommendation on the Ross piston. I expect that's exactly what I'll do when it comes time to rebuild. What gasket combo would you recommend to get the best compression/squish?

On the cam issue, I actually tried running the GT Thunder cam several months ago (which I believe is essentially the same thing as the Web 450/451) and it just killed too much bottom end for my tastes (I'm running the JE 10.8-1 with a Sparks pipe for cross country racing). I've thought about trying either the TC XC cam or the Web all-around. I don't know anything about the 479. Would it provide more bottom end than the 450/451?

I am also seriously considering the FST oil cooler. I just need to see how it mounts up to make sure it won't interfere with my WER steering damper.

Thanks again for all of the information. 440EX4me, good luck on that engine!



11-14-2002, 08:39 AM
If you want an Oil Cooler, Dave at Dirt Mods makes one that fits where the stock cooler goes, it's just bigger. I would rather have that setup over a FST.

Matt Fisher
11-14-2002, 09:47 AM
Don't sweat the .040 vs .055 squish. Just ride it and see what you think. Like you said, you can always take it apart again...

Squish is independent of the dome. The dome affects quench. In theory, the best scenario is having a very small area in the combustion chamber for the "explosion" to occur in. On the other hand, with multiple valves, it's nearly impossible to do so. You sacrifice combustion chamber efficiency for more airflow.

A good example of where squish is more important would be on a 2 valve V8 motor. Look at the current SBC heads. They're all closed chamber, with a fairly large squish area. A "pocket" around the valves makes up the combustion chamber. Quite efficient, but a 4 valve version will flow more air. There's some caveats to that, but you get the idea.

What displacement are you running? Yes, the GTT cam is the Web 450/451, W Bros Track Cam (and probably some of the tuners "custom" cams). Hopefully I'll be able to give everyone a very specific compario of the 479 Vs 450/451 soon, as my friend's motor has the 479. It should provide slightly better bottom end, a little better mid, the same top-end, with more throttle response than the 450/451.

You could easily change the mounting arrangement of the FST cooler. It might require welding some tabs on the frame elsewhere, no biggie.

On the Ross pistons- unless you want to start milling cylinders/piston domes/combustion chambers, just assemble it and ignore the squish. That's the trade-off to having a domed piston. Nothing's free.

That's a great idea, a larger main cooler would work great. The FST cooler cools the oil going into the head, which is rather important considering the RFVC head is known for creating excessive heat. This causes detonation, and (possibly) is responsible for the rocker issues that plague high-lift cams. I'd suggest both, truth be told.

11-14-2002, 10:29 AM
I think I may have been confusing squish and quench again :Grr But now my brain may have been gettin more "squish" too.

Dhines I know what you want but as much as I had tried to get a "fits all" solution to this the more it was apparent that there wasnt any.

The best thing I can offer from my experience with this never ending project is that you need to decide on what you want and start it going. So get the kit you like or purchase the parts seperate (my preference) and have the boring done and assemble the piston rings and cylinder and take some measurements. Then you will know if you need to do any decking or gaskets changes etc. and also you will have all the info to work out the numbers for what ever design changes you like.

You have to get the basics and go from there. Not the easiest way but the better way.

There was some very good info on cams earlier in this thread so take a look there too. It was interesting to find how many of the different branded and "builders" cams were off the shelf web cams.

I decided to take some time and get this thing fired up today so the fingers are crossed. :)

11-14-2002, 02:58 PM
Matt, If I went for cooling products I think I would get the XR's Only big fin head fit and that Dirt Mods bigger stock replacement cooler. How do you think that would work? Heck XR's Only says 30 degrees with the big fin head and I'm sure that cooler would do that or more.

Matt Fisher
11-14-2002, 04:00 PM
A larger main cooler is quite appealing. I almost used the OEM cooler for the cam, and my custom one for the motor.

Although the big fin kit probably works great, I wonder if it would be as effective as the oil cooler. On a dirtbike, the room for a cooler is quite limited, but we don't have that issue. Since the FST design places cool oil directly into the camshaft's center, I'm thinking it will do a better job of cooling that component. I believe FST claims a 50 degree drop in oil temp. After seeing how small the OEM lines are (and therefore how long the oil is in the cooler being cooled), I tend to agree with that.

-I would not be excited about the cooler running out of oil (by mounting it upside down), because it would be quite some time before enough oil made it to the cam.

I was unable to find the big fin kit on the xrsonly site, what's the cost?

BTW- I got my sleeve from Advanced Sleeve. They also supplied me with the Cometic gaskets. Around $40 for everything, if memory serves me correctly- It was much cheaper than LA Sleeve and Cometic directly.

11-14-2002, 07:53 PM
The Big Fin kit is $250. Oldnumber7 has it and really likes it on his 465. He said during his dyno runs that they had to turn off the fans because it was running to cool. I think they would be well worth it, and look trick.

11-15-2002, 05:52 PM
Its ALIVE !!!

Had made some time on Thurs before I left for a day and got the balance of the motor etc assembled and fired her up. Sounds good so far and may get some break in/seat time tommorrow if the weather holds out and will let you all know what I find.

Ended up with the 12.5:1 (dbl .012 and .020 base gaskets) and loaded it up with some 112 cam2 and now its smeeling better too.

As far as the aux oil coolers go does anyone have recomendations on where to get a "replacement " cooler and what is it from? (honda chevy etc.) I am thinking on just creating my own set up and am not crazy for the tranz cooler set up.

11-15-2002, 05:54 PM
I bought a auxilery univerasal trans cooler at a autoparts store and it works awesome just make sure however you mount it that it has rubber between frame and cooler

Matt Fisher
11-15-2002, 07:32 PM
The one I used was off a Mitsubishi Starion Turbo. It looks like the OEM one, just 2X+ the size.

It's important to block off the oil line going to the cam (if you're using the FST design). I used a BB and some JB Weld. Let me know if you want more specifics.

I mounted mine solidly to the frame, though might add some anti-vibe spacers later.

Great job!:macho

11-15-2002, 08:52 PM
Ahh the moment of truth has finally arrived, glad to here it's up and running. Fill us in on how it performs, I hope she rips. My project will start later this winter on a stock 01 so we can go though this fine exchange of thoughts all over again lol.
Thanks again to all the contributors on this interesting topic...

Matt Fisher
11-17-2002, 09:32 AM
Mine lives too.

Rode it around for about 30 min yesterday, just breaking in the motor. I'll probably do the same again today.

Initial feel- about like the 12.5:1 on race fuel felt like. But it's been several months since I've ridden it, so take that with a grain of salt.

11-17-2002, 06:58 PM
Mine lives too.Rode it around for about 30 min yesterday, just breaking in the motor. I'll probably do the same again today.

Glad to hear that. Hope it lives up to your expectations :)

I had about a 1hour reprieve from the monsoon were having around here the last couple days (since the motor was assembled :( ) But it does sound pretty good and the original vibration seems to have gone away while setting the rings . If time and weather allow I hope to get a chance to break it in right on mon or tue.

And one more thing... you just cant beat the smell of cam2 :D