WTK which hi comp piston to buy?

[FastHonda400ex]

I want to buy a hi comp piston for my 400ex, but still run super unleaded pump gas. Which brand should I look at- Ross, JE or ? I'm thinking of leaving it stock bore , or bore it to a 416. Any input would be greatly appreciated.

Thanks,
Doug

[Steve-o 400EX]

Ross or JE, its ur call. Go with 10.5 or 10.8 compression ratio. I might try a Ross if I were you. I heard they are a little better than JE. Either or is good though. I am puttin in a 416 with a JE next week. Stay away from wiseco, they do not have the compression that they claim they do, 11:1 is more like 9.5:1 from what i've read. Call C&D racing, theill hook ya up, its where i'm gettin my parts.;)

I would go with a drop in cam while ur at it, maybe a hotcams stage 1. This will make it perform a little better.

[FastHonda400ex]

Steve-o,
I'm getting a new Stage 2 Hotcam from a fellow exrider, that I'll be putting in at the same time. How many horses can I expect from a hi comp piston and the cam ?

[JD400exrider]

If your putting in a stage 2 cam i would bore it out to at least a 416. Not anymore money other than a bore job. When it is apart may want to think about port and polish and a valve job. Each mod cpomplimants the other for better performance.
The Ross piston is just a little lighter in weight. Should rev a little higher. Either one Ross or JE will be fine.
I think the compression difference on the weisco pistons is only on the 440 pistons, but not sure.

I should have my JE piston by the end of the week (when the big brown truck gets here ) :D
Talk to C&D they will set you up.
Good people and good service.

[Steve-o 400EX]

Originally posted by JD400exrider
If your putting in a stage 2 cam i would bore it out to at least a 416. Not anymore money other than a bore job. When it is apart may want to think about port and polish and a valve job. Each mod cpomplimants the other for better performance.
The Ross piston is just a little lighter in weight. Should rev a little higher. Either one Ross or JE will be fine.
I think the compression difference on the weisco pistons is only on the 440 pistons, but not sure.

I should have my JE piston by the end of the week (when the big brown truck gets here ) :D
Talk to C&D they will set you up.
Good people and good service.

I agree, but wiseco pistons have this prob with all their pistons, at least for atv's. It will cost another 50 bucks to bore it, the piston is the same price. I am gunna do a port and polish but not until the summer. With a high comp piston you should expect low 30's in hp, maybe 31 or 32 at most.