11:1

[yellowex26]

How big of a difference will I feel if i put a JE 11:1 piston in my 400ex?

[ZeroLogic]

whats the bore size?

[Toadz400]

It'll make quite a difference no matter what bore size, but if you combined the higher compression piston with a bigger bore, porting, and aftermarket cam you would see quite a big difference.

[yellowex26]

It's sotck bore. Im gettin it for pretty much of nothing. it needs rings and thats all

[Joe400ex]

i am doing a 416 with a 11:1 comp next winter and a port and polish, stage 1 or 2 hotcam( dont know with one yet) and a 14tooth front sprocket. People tell me that u will feel a huge diff:)

[Toadz400]

Originally posted by Joe400ex
i am doing a 416 with a 11:1 comp next winter and a port and polish, stage 1 or 2 hotcam( dont know with one yet) and a 14tooth front sprocket. People tell me that u will feel a huge diff:)

Keep the stock front sprocket, you will not need a 14 tooth with the higher compression 416 and a stage 1 or 2 cam. You will have plenty of power, if you go to the 14t you will just be revving out way too quick in each gear unless you drop some teeth in the back or get bigger tires.

[m1ke]

i imagine you need to upgrade your crank and connecting rod for higher compression ratios as there not designed for that extra compression?

[ZeroLogic]

Originally posted by m1ke
i imagine you need to upgrade your crank and connecting rod for higher compression ratios as there not designed for that extra compression?

You might, for 11:1 compression you don't have to for like 13:1 compression probaly.

[bwamos]

Originally posted by m1ke
i imagine you need to upgrade your crank and connecting rod for higher compression ratios as there not designed for that extra compression?

You'll be perfectly fine for 11:1

[400exrules]

u dont need to do anything to the crank with an 11:1

and yes it will make a noticable difference. Might as well make it a 416 while your at it, but you might want to run race gas with 93 pump, 50/50 to be safe

I cant run just 93 I run( for trails a 75% c12 or less and the rest 93.
For racing I run just c12. I only use about a quart of gas per race day.

[wboy62417]

i have one of the 11:1 wiseco pistons and it does a lot of good i felt a power diff. dont have to do anything to the crank race gas is good if you want to spend the money if not just put pump 93 in it it will be ok runs fine in mine DONT RUN 89 or 87 it will dog out really bad and you wont have alot of power

[bwamos]

Originally posted by mittimj
I cant run just 93 I run( for trails a 75% c12 or less and the rest 93.
For racing I run just c12. I only use about a quart of gas per race day.

You're running without a base gasket and a XR head gasket no? That would raise your compression beyond the 11:1 ratio, I beleive. ;)

I reserve the right to be a tard when it comes to 400ex's. hehe. I know my 300's and that's about it.. lol.