high compression, race fuel questions

[400man]

would there be much difference in noticeable power between a 416 12:1 and a 426 13:1 with a stage 2 cam? Im gonna build me a high compression motor but can decide what to go with. been reading ALOT about both 416 and 426 builds and both seem to have their pros and cons. I have access to 110 octane race fuel and gonna do the heavy duty studs for sure. would the 416 be more reliable but make less power then the 426? this is gonna be a trail/XC race motor and im wanting more power in the mid/topend.

[JOHNDOE83]

The 440 is just as reliable as the 416 and both are just as reliable as the stock piston, there is no difference in reliability when getting bigger pistons.

Bigger will always make more power, 416 is more powerful then stock, 440 is more powerful then 426 etc...

High compression motors are nice! you can raise the compresion even more by shaving the head.

[jcs003]

i had a 435 JE hi-comp with a web cam and port work and etc. it was a beast. had the work done by four stroke tech. he added an extra oil cooler. i used 10 or 112 octane. go for that kit. if not get a 250r. thats the only bike that can compete but its harder to ride.

[TRXRacer1]

The more HP you pull out of an engine the less reliable it is. Common sense..... make something work harder it won't work as long as before. Shave the head on a 4 stroke and you change cam timing. Everything you do has an effect. A 13:1 will be harder on your bottom end and run hotter then a 12:1. Enough to be afraid of, maybe, maybe not.

If you're building an air cooled motor for trail/XC then you might want to consider the consequences that lead to more heat. More heat...... more issues with detonation. If you were building a track machine that will have some good air movement I'd say go 426 13:1 and know that you need to resleeve when you need another piston. For an XC machine I'd stay below 12:1 and just go for the 416 so you have serviceability in your stock sleeve yet.

How much HP are you looking for? Where do you want the majority of your power to be? Are you doing other mods? Building a hot engine for technical riding might not be your best option.

Just so you know what jcs is talking about a 435 is a 440.

[jcs003]

again. its a 435 NOT a 440.

http://www.jepistons.com/Catalogs/Powersports/ATV-UTV/Honda/trx_400ex.aspx

[TRXRacer1]

Originally posted by jcs003
again. its a 435 NOT a 440.

http://www.jepistons.com/Catalogs/Powersports/ATV-UTV/Honda/trx_400ex.aspx lol, you're funny dude. All big bore 440 kits are 435's. It's just what they call them. You have what is traditionally called a 440.

[jcs003]

Originally posted by TRXRacer1
lol, you're funny dude. All big bore 440 kits are 435's. It's just what they call them. You have what is traditionally called a 440.

maybe JE and wiesco should accept all common terms. your a fool.

[TRXRacer1]

Originally posted by jcs003
maybe JE and wiesco should accept all common terms. your a fool. What about the other brands? What about all the custom pistons some engine builders use? The 440 kit has been around well over a decade. Sorry I was the one to break it to you.:ermm:

[400man]

Originally posted by jcs003
i had a 435 JE hi-comp with a web cam and port work and etc. it was a beast. had the work done by four stroke tech. he added an extra oil cooler. i used 10 or 112 octane. go for that kit. if not get a 250r. thats the only bike that can compete but its harder to ride.

I had a 250r before I got my 400ex. it was moderatly built ( 260cc, porting, carb, reeds, high compression, etc.) and at one time it was a damn strong running bike, would eat a 450 every time in a straight up drag race, but it went downhill after that cylinder broke the sleeve, ran it too long on the same piston :(

I got my 400ex cause they are damn near bullet proof and you can just jump on and ride with worrying about breaking anything. and coming from a 2 stroke to a 4 stroke, for woods riding/racing I like the EX's power a little better, its ALOT easier to ride in tight trails and the torque makes it easier to poke around on and stuff

[tayyo789]

If you want the 400 because its reliable, I would stick with the 416 like TRXRacer1 said.
There are a couple guys on here who will tell you that 440's are reliable, but the truth is that they are not, especially for racing. In order to keep the 440 from breaking stuff you have to do too many other things, IMO. The 416 makes plenty of power, and would be fine. I actually feel that my 416 runs way better than my 440 ever did

[400man]

so I guess a 416 would be the way to go. all im wanting is a good responsive, snappy motor that pulls good from when you punch the gas all the way to the high revs. I know the saying "compression makes power" and im deffinatly going with either 11:1 or 12:1 for sure with hd studs. Im only wanting to tear the topend apart once, so i'll be doing the piston/cam together and I also got a spare lightened flywheel i'll be putting on with it. im reading about cams and what kind I would need to get the power im wanting. im wanting to stay away from the "hardened rocker" cams cause I dont want to put much money into head work right now. i'll look into that later on when or if I get the head ported, then probably get hd valve springs and rockers and stuff. and it looks like I could get buy with 50/50 mix of race fuel if I went with an aggressive cam and 12:1 piston.

[TRXRacer1]

Hotcams makes some pretty good cams and as long as your valve springs are within OEM spec you don't need to change a thing.

I did a 416 with the stage 1 cam and it was an absolute stump puller. I have another 400 that I'll be building soon and this time I'll go stg 2 or 3. The stg 2 is your best cam for your average build, the 3 is just a little wilder. Although none of the 3 are "radical" they all make the stock cam look like a *****cat. You will need to get into a hardweld cam for true all out race.

just run some u4.2 or Q16

[JOHNDOE83]

Originally posted by tayyo789
If you want the 400 because its reliable, I would stick with the 416 like TRXRacer1 said.
There are a couple guys on here who will tell you that 440's are reliable, but the truth is that they are not, especially for racing. In order to keep the 440 from breaking stuff you have to do too many other things, IMO. The 416 makes plenty of power, and would be fine. I actually feel that my 416 runs way better than my 440 ever did


This is not true, my 440 doesnt have heavy duty studs or a heavy duty cam chain, I race it all the time.

It is a super reliable race motor.

[tayyo789]

Originally posted by JOHNDOE83
This is not true, my 440 doesnt have heavy duty studs or a heavy duty cam chain, I race it all the time.

It is a super reliable race motor.


From every post of yours that I have ever seen, it seems like you drag race it, please correct me if I'm wrong about that, but any other application will get the motor much much hotter, which is what causes the 440's to blow.

[hypersnyper6947]

Originally posted by tayyo789
If you want the 400 because its reliable, I would stick with the 416 like TRXRacer1 said.
There are a couple guys on here who will tell you that 440's are reliable, but the truth is that they are not, especially for racing. In order to keep the 440 from breaking stuff you have to do too many other things, IMO. The 416 makes plenty of power, and would be fine. I actually feel that my 416 runs way better than my 440 ever did

What he said. I had a 440. It welded 2 valves into the piston lol. My 416 is faster, runs cooler and is more reliable. If your trying to build something with that much power you started with the wrong quad. Dont get me wrong you can make the ex quick, but enjoy the reliability.

[JOHNDOE83]

Originally posted by tayyo789
From every post of yours that I have ever seen, it seems like you drag race it, please correct me if I'm wrong about that, but any other application will get the motor much much hotter, which is what causes the 440's to blow.


I actually trail ride it with the same mods for hours on end....along with drag racing it......never had a problem....ever.

There would have to be another issue that was overlooked upon install that made a valve weld itself to the piston.

[tayyo789]

Originally posted by JOHNDOE83
I actually trail ride it with the same mods for hours on end....along with drag racing it......never had a problem....ever.

There would have to be another issue that was overlooked upon install that made a valve weld itself to the piston.


There are about 3-4 people on this site that have had no problems with their 440's. You are one of them.

I'm not doubting that your's doesnt have problems, but the evidence shows that 440's are historically unreliable. I'm just trying to help the guy from making a decision that statistically shows he'll be spending more money

[flyboy1294]

Originally posted by tayyo789
There are about 3-4 people on this site that have had no problems with their 440's. You are one of them.

I'm not doubting that your's doesnt have problems, but the evidence shows that 440's are historically unreliable. I'm just trying to help the guy from making a decision that statistically shows he'll be spending more money

I hear what you're saying definitely.

I am a strong believer in being proactive when it comes to dealing with common issues. I think it is possible to have a reliable 440 and get a significant amount of power out of it. But you HAVE to put more money into them than your typical 416 or 426. I'd go so far as to say that HD studs, HD Cam chains, SPAL fans, and longer duration cams are a must with a 440.

Most people just slap a bigger piston in there and expect to have increased performance and the same reliability as stock - Not true. For the piston to work to its full potential it needs a cam and possibly head work. For reliabity to be maintained you've got to be preventitive with good quality gaskets and other parts that are known to fail. In a nutshell, more cc's = more air and fuel = more of a boom. = more room to fail.

So I do agree with you when you say people have more issues with 440s. But if you look more closely, a lot of it is user error.
(I know you are probably well aware of everything I stated above, I was just trying to give an explanation to my opinion.)

[tayyo789]

Agreed, but I feel that it really isn't worth the trouble with this motor. The power gains over the 416 aren't anything worth bragging about, especially when comparing the costs, assuming the 440 had everything else necessary to complete it as you mentioned. The rest of the market is so horsepower obsessive, that people want to take what they have and buy all the go fast parts for it, instead of getting something more fitting for that personality from the get go. The ex is one of those bikes that really is more introductory level when compared to the bikes that us ex riders want to compete with. Oh god I'm rambling...

My opinion in a nutshell: 440 = more issues than its worth. If you wanna go fast, get something else

[flyboy1294]

Originally posted by tayyo789
My opinion in a nutshell: 440 = more issues than its worth. If you wanna go fast, get something else

I can agree with that.

[tayyo789]

Judging by your sig, you did it right. What kind of problems have you had? Did you do all the work yourself?

[flyboy1294]

The only problem I had was over-heating.

I took the engine apart to get my cases powder-coated and found the scraps of the old piston and sleeve still in the bottom of the motor. So I looked at the piston and sleeve, and the previous owner had just thrown a 440 in there and it was showing some wear. He DID use good gaskets so I didn't have any issues that way, but I decided that I needed to rebuild it right when I had it apart. Went with P&P, a better cam, Wiesco piston, hone and mill of the head gasket surfaces, HD studs, HD chain, Oversize valves and springs etc. I don't want to have to take it apart until I want more power. :p

[F-16Guy]

If you don't mind running race fuel or converting to E85:

-- JE 87mm (416) 12:1 piston
-- Carrillo connecting rod
-- HotCams stage 2 cam
-- GT Thunder HD studs
-- FST style secondary oil cooler
-- CRF450R cam chain
-- 04-05 TRX450R carb
-- mild clean-up port
-- Good aftermarket intake and exhaust (if you don't already have it)

The Carrillo rod and HD studs will give you better-than-stock reliability. The FST style secondary cooler will cool the engine oil just before it's forced through the cam and through the top end, which is where most of the heat is. The 12:1 piston, stage 2 cam, clean-up port, and 450R carb will give you a huge increase in power across the board. It won't be a budget build since you'll be into the bottom end to replace the rod, but it will be built right and give you tons of power with stock-like reliability.

[400man]

Originally posted by F-16Guy
If you don't mind running race fuel or converting to E85:

-- JE 87mm (416) 12:1 piston
-- Carrillo connecting rod
-- HotCams stage 2 cam
-- GT Thunder HD studs
-- FST style secondary oil cooler
-- CRF450R cam chain
-- 04-05 TRX450R carb
-- mild clean-up port
-- Good aftermarket intake and exhaust (if you don't already have it)

The Carrillo rod and HD studs will give you better-than-stock reliability. The FST style secondary cooler will cool the engine oil just before it's forced through the cam and through the top end, which is where most of the heat is. The 12:1 piston, stage 2 cam, clean-up port, and 450R carb will give you a huge increase in power across the board. It won't be a budget build since you'll be into the bottom end to replace the rod, but it will be built right and give you tons of power with stock-like reliability.

well now thats something I havent put much thought into......the crank. my 400 is a 2000 model, with the original crank/bottom end. if I decided to go with a 12:1, would it be hard on my crank and possible make it wear out sooner than normal. when I re-ringed the motor last fall, the crank and bearings apeared to be in good shape with no excessive play.

[F-16Guy]

There have been issues in the past with the connecting rod breaking with a very high compression engine (12:1 or more). I think 12:1 would be borderline as far as the stock conrod goes, but if you want reliability, an aftermarket rod is a good idea. As many 400ex's as there are out there, you could probably find a new complete HotRods crank assembly on ebay for cheap. That may save you a few bucks if you do the labor yourself and just swap out the whole crank assembly. When I built mine, I had a Carrillo rod installed ($175 direct from Carrillo Ind.) by Powroll. I can't remember what the total cost was for the bottom end, but it's typically about $300 to split and re-assemble a bottom end, plus about $75 to install a new connecting rod onto your stock crank. Carrillo advises to re-use your stock lower rod bearing. You can't buy a new one separately, and my stock lower bearing has been fine in the new rod. I have several years on it. My build has been rock-solid reliable, even after several rounds of WORCS races and a few trips to the dunes. It doesn't burn or leak a drop of oil, and it's nice and quiet internally.

I have an 11:1 piston, and I only replaced my conrod because of a failed wristpin circlip that allowed the piston to damage the upper conrod bushing. If you choose to go with 11:1, or possibly even 12:1 with a smaller bore (406,416), you'd probably be fine with the stock rod. That would save you quite a bit of money. I would still do all of the other stuff, though (carb is optional, but a nice increase). The secondary cooler really brings the temps down, which is important with a head with sub-rockers (more friction and heat). Head studs are mandatory, in my opinion. You might get away with not having them, but for what they cost, do you really want to take the chance? I wouldn't.

[Fanged03]

Dang F-16 guy now you got me worried. I'm doing a 416 12.5:1 sparks piston and dind't plan on changing the rod. My plan was just what you recomended 450 carb on e-85 but no rod or cooler.

Brent

[TRXRacer1]

Originally posted by Fanged03
Dang F-16 guy now you got me worried. I'm doing a 416 12.5:1 sparks piston and dind't plan on changing the rod. My plan was just what you recomended 450 carb on e-85 but no rod or cooler.

Brent If you run E85 you might not need the cooler. My temps seriously dropped with that stuff.

[F-16Guy]

Originally posted by Fanged03
Dang F-16 guy now you got me worried. I'm doing a 416 12.5:1 sparks piston and dind't plan on changing the rod. My plan was just what you recomended 450 carb on e-85 but no rod or cooler.

Brent
Yeah, that may be on the edge a little. If you're going to run 12.5:1, I'd recommend staying with the stock CDI so you don't over-rev it. Running E-85 is a good thought, too -- not to mention much cheaper and easier to get than race fuel.

If you have HD studs, good gaskets, everything is assembled correctly, and your jetting is correct, I wouldn't worry too much about it.

[flyjum]

12:1 Comp
Cam
ported head
Rev box
450r carb
91 octance with a good octane booster( nos or lucas work the others dont).
This should run great and make pretty good power all the way to high rpm.

A little something on fuels.

E85 is a good fuel and will keep you runing cool. The problem is the distaltion curve can make it bog at low intake veolcitys( low rpm or low throttle postion) aka alcohol flat spot or methanol bog.

It will also make it super hard to start because it does not want to vaporize very easy but it will last longer then pump gas. Avgas has this same problem but for diffrent reasons.. The reason is they run it at higher elavation so they dont want bubbles to form in the gas lines and "vapor lock" so the curve is much higher they pump gas.
The real octane of e85 is 101-104 while 100ll avgas is 96 R+M/2(aki pump gas rating). Avgas has a small amount of lead in it this will not effect your quad (unless you have a o2 sensor). You can bump 91 octane to 96 with just octane booster and not have the problems with e85 or avgas.


The cam lowers the dynamic compression ratio so you can run higher compression ratio but run pump gas.

The new dirtbikes come 12.8:1 cr and run on pump gas.

The ninja 600 has 13.3:1 and is pump gas. The cam size affects the compressio ratio as much as the pistion does.

[TRXRacer1]

Originally posted by flyjum


E85 is a good fuel and will keep you runing cool. The problem is the distaltion curve can make it bog at low intake veolcitys( low rpm or low throttle postion) aka alcohol flat spot or methanol bog.

It will also make it super hard to start because it does not want to vaporize very easy but it will last longer then pump gas. Never had a low end bog from E85 and you are dead wrong about hard starts. There is no noticeable difference in starting an engine with E85 compared to pump gas. None. Also E85 is 105 around here.

[Fanged03]

Cool thanks for the info guys. That was the last thing I was wanting to do is put a rod in this thing. I am getting sick of sticking money into this little motor. Should be a bad little dude though. 12.5:1 Sparks JE piston, Hot Cams St2, Kibblewhite Valves and Springs and guides, Home port clean up, 450 cam chain, gonna lighten up the flywheel, 450r carb on E85, Gonna try to keep in the sparks ignition key. While I was doing all that I decided to tear the frame apart and gusset it and get powdercoated. So all in all I will prolly have 2/3 of what a used 450 would cost me around here. haha The 400 is just so much more comfortable

Brent

[flyjum]

Originally posted by TRXRacer1
Never had a low end bog from E85 and you are dead wrong about hard starts. There is no noticeable difference in starting an engine with E85 compared to pump gas. None. Also E85 is 105 around here.

Alcohol causes bogs e85 is 85% alcohol it does have a bog under low velocity conditions. Maybe your carb is too small for your bike so you have decent intake speeds at low rpm. FCR carbs dont have it so bad because the AP can be retuned to help fix it.

E85 is harder to start then pump gas. If its dialed in right its not much harder but still is harder then regular pump gas. This is because it does not vaporize as easy as pump gas.

I have tuned many e85 bikes and they all have the same problems.

Its a great fuel for drag racing and desert racing but for other types of racing its not so great. It works good at wide open throttle.
Also you need to run a a/f of around 8:1 to make the most power out of e85. Pump gas is around 12:1 afr.
This is why it "runs cooler" because alot more fuel is being used and can cool the combustion chamber alot more.

[TRXRacer1]

If you've had issues with starting then you must not have had something dialed in correctly. I will not argue to whether or not there is a difference but in all the machines I have set up to run on E85 I have yet to notice that difference. This is one of the reasons they blend in 15% petroleum in normal sumer conditions and even more in winter climates. E85 can be E70 without the consumer knowing it depending on the season. Your claim of E85 not even being 105 octane is totally bogus. The posted rating takes this in to consideration and since ethanol is 129 octane E85 is actually quite a bit higher then 105 depending on the time of the year.

As to if the carb is too small for the machine I doubt the 40mm I have on my 400 is too small considering it's internally stock. You seem "book" knowledgeable on the subject but I detect a lack of real world experience. Your comparisons to methanol are a bit concerning too. They may be relatives but not sisters. Set-up and characteristics are vaguely similar.

I do not buy for one second that you have tuned many bikes for E85 because if you had then your posts would read completely different. If you have indeed done the work you claim then you're not that good at it. If that is the case then I can only offer this. In many situations the stock needles will not allow the low-mid to get enough fuel and if you try again you may want to look into custom. It has been necessary in a couple of my builds. This will alleviate the bog that seems to haunt you.

[flyjum]

E85 is 105 MON octane. The RON is lower by alot.
AKI octane rating is ron + mon / 2.
On this scale its 98-104 octane with a average of around 100-102. Also the posted rating is 85.
The reason for the 15% gasoline is to help starting with vapor. It does not solve the problem. Your claim that you have had zero starting or bog issues is not true. The distaltion curve makes it a diffcult fuel to vaporize.

The needle is not the problem nor is the tune or any other thing besides the fuel it self.

[TRXRacer1]

Originally posted by flyjum
E85 is 105 MON octane. The RON is lower by alot.
AKI octane rating is ron + mon / 2.
On this scale its 98-104 octane with a average of around 100-102. Also the posted rating is 85.
The reason for the 15% gasoline is to help starting with vapor. It does not solve the problem. Your claim that you have had zero starting or bog issues is not true. The distaltion curve makes it a diffcult fuel to vaporize.

The needle is not the problem nor is the tune or any other thing besides the fuel it self. You really don't have a clue.