Have you Decked the cylinder

Matt

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.

[leel]

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)?

Thanks,
Lorrin

[Ononewheel]

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....

[MR. HONDA EX'S]

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?

[MIKE400EX]

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.

[MR. HONDA EX'S]

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.

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]

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.

I replaced the stock head and base gasket last week and this is what I found:
STOCK GASKETS
The JE 10.8/1 piston had a deck ht. of .028
Compressed thickness of stock head gasket- .035
Compressed base gasket- .020

XR GASKETS
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

Matt,

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 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.



2slow

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.