largest piston in 400ex without resleeving

[my99ram]

is a 88mm piston the largest that will fit without resleeving?
I was looking at the 87mm je piston nd it says requires boring and plating,whats the plating?
87mm=415cc
88mm=426cc
am I right?

[HondaRacing83]

87 is a 416. they require boring but not plating. you have to resleeve for a 440. do wiseco not je

[my99ram]

Originally posted by HondaRacing83
87 is a 416. they require boring but not plating. you have to resleeve for a 440. do wiseco not je
i hear alot of pistons freezing from weisco.is numara and pro x a good piston

[HondaRacing83]

no. they are the worst especially namura. wiseco is the only way to go if you want a good motor. maybe je but ive heard tgey melt too.

[Drfat400ex]

Originally posted by my99ram
i hear alot of pistons freezing from weisco.is numara and pro x a good piston Namura... Please don't put in one of those go wiseco or CP as far as I'm concerned those are the only good ones.

[HondaRacing83]

yeah i forgot cp is good

[dxcody]

Idk what the deal with Namura is.. i mean they are made of the same thing that the stock 400ex piston is... they just must not be made very well.

All i will run is wiseco or JE. CP is out of my price range.
Hadnt really heard anything bad about JE,

did you guys hear that they melt too ?

[Zakradu398]

I've never heard bad from JE. Almost just went with there's but stuck with Wiseco.

[HondaRacing83]

i swear ive heard of 1 or 2 je melt but wisecos amazing. cp is pricey.

[chronicsmoke]

6 years on a wiseco 10:1 426 piston, not pounded but well used..

2 years of a JE 13:1 SB piston in my 450r that gets Pounded..

No problems with either :cool:

My pereference;
1)CP
2)JE/Wiseco
3)Namura/Pro-X <-make good 2T pistons though..

[powerbomb400]

Wiseco,CP are forged pistons. Namura are cast pistons like the factory pistons. Namura buys over runs and put there name on them. I'm a Wiseco piston person myself. They make a good quality piston and have been in business for years.
Plating is a nickel cadium plating on the cylinder bore instead of a steel sleeve. I myself would rather have a steel sleeve. If you go with a 416 you can always bore a sleeve to make it a 426. With the plating after you bore it you have to send it out and have it replated.

[CJM]

Bore size does not equate to massive gains in power, compression does.

IE a 426 vs a 416 with the same 11:1 compression piston and everything else the same will be almost damn near equal.

My friend has a 407, same exact setup as me pretty much and its no slouch. yea its not as fast as mine but it still has a stock exhaust and closed airbox lid. Another friend had a 416 all done up same as me pretty much-we were equal if not he was slightly faster (gearing, exhaust, rider ability, etc) in a drag race.

Do a high compression piston with a 407 if you want to bore it, spend time on the exhaust, get some mild porting done and a 450r carb and be very happy.

As for pistons: Wiseco, JE or CP. I prefer wiseco, had 2 of them so far no issues, built a friends with one and no issues. JE and CP are nice but mroe $$. Namura is cheap crap, seen more than a few melt.

[Pittsburgh400ex]

CJM pretty much hit it on the head. Originally i did the sparks racing 416 kit. It was a beast while it ran..just wasnt very long. Was JE 12.5:1

Running 11:1 wiseco 426 now and its not the same power by any means. However...it hasnt melted around the rings and scored my cylinder either. So from now on ill only use wiseco. Some people swear.by JE, im not one of them.

You want power, man go grab a 450. I didnt realize the difference until i had both and ran them back to back. Nit even compareable really, and my 450 is just mildly tuned.