compression

[blue]

I'm thinking of putting a higher compression piston in my 400EX. Has anyone had motor or head problems? What compression ratio would be best 10:1 or 11:1? Also, where is the cheepest place to get a Wisco piston kit?

[Jingle #11]

well it really depends if u wanna run race gas you could go with a 11:1 u could go 50/50 mix of race gas and premium. Or you could run staright pump gas with the 10.8:1. I rode a 12.5:1 416 last night and it was pretty cool. it pulled alot harder than my 400. If its just trail riding and maybe a little play racing then i would go with 10.8:1

[TC426EX]

Go 11:1 or 10.8 :1... If you are using the stock bore you should be ok, but if you go any bigger, make sure you either Heli-coil the head studs or get a heavy duty kit from East Coast ATV. If not, then blowing head gaskets will most likely be your new hobby...

[hondarider2006]

Before this thread gets really long, what kind of riding do you do? If you are looking to just run pump gas, run a 10:8.1. Spend a little extra $ and get a 416:)

[04'400ex'er]

Originally posted by hondarider2006
Before this thread gets really long, what kind of riding do you do? If you are looking to just run pump gas, run a 10:8.1. Spend a little extra $ and get a 416:) I'll second this. Also, I'd do the heavier rod. The 416 would kill the high comp 400.:rolleyes: so, it's worth it.

[blue]

i race a little do alot of trail riding. i want to race more though. i just dont want to bore my motor. i want to run pump gas. where can i find the 10.8:1?

[hondarider2006]

Give C&D racing a call, they have a special going on the JE pistons right now;)