What compression

[circa411vm]

im rebuilding my 04 450r and i dont know wich compression piston i should use. Some people told me CP piston but there is 11.0:1 or 13.0:1

i have hrc kit, with dg exhaust and HCII

[BlaineKaiser450]

Anything higher than 12.5:1 you'll have to run race gas. If you are okay with the more expensive gas, you can do 13:1 or 14:1. If not, run a CP 12.5:1. I like mine a lot

[circa411vm]

ok but what the number of octane of the gas you using with 12.5 ?

[Scro]

I've ran 93 on 12.5:1, and it was fine.

[d3ktrix]

I also run 12.5:1 on 93.

[ricks450]

Originally posted by d3ktrix
I also run 12.5:1 on 93. even with the new ethanol in the gas?

[d3ktrix]

Originally posted by ricks450
even with the new ethanol in the gas?

New? Haven't they been putting ~10% ethanol in gas since before I was born?

[400exBRAAP]

yes. just shake your wheeler before starting it to mix the ethanol all up and stuff. if not it'll run like a turd for lke 5-10 minutes

[ricks450]

Originally posted by d3ktrix
New? Haven't they been putting ~10% ethanol in gas since before I was born? not going 2 say it wasnt 10% 4 long time. but they only been advertisin 4 bout 2 1/2 years maybe 3. and i personally no 4 a fact theres been more added (or) they just started using it. the self life isnt no where near as long as it use 2 b. funny how all these marine engine guys started havin problems when they did. and put it n a older model car thats got a carbrated V8 in it. ull have 2 pull the timin way bay back 2 keep it from knockin the bearins out the bottom of the motor. they spark knock like crazy. put in a stock Z28 and that will show u. these regular gases aint worth a **** no more.....personally i wouldnt run anything under cam2. if your buildin anything worth a crap. JMO i run cam2 n my bike and im 12.5:1. 2 number 1 reasons i no im safe and it smells good burnin?

[06 Honda 450R]

put a 15 to one in it and run 87 octane, it will run like a champ

[Pacheco_450r]

I just installed a CP 12:1 in my 05 this winter and it's running real strong. I was told I can run 91 with it, but i run 1/4 race mixed with 91 pump with it just to be on the safe side.

[ricks450]

Originally posted by 06 Honda 450R
put a 15 to one in it and run 87 octane, it will run like a champ lmao, :D