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CP piston
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Posted by: THEMACHINIST

is someone have try the piston Cp 12.1 or 13.1.cause ive here they are made for gas pump?

Posted by: spanky101

13:1 would lead me to belive you would need race gas? ive always thought about 12:1 is the highest your gonna wanna use on pump gas.

Posted by: THEMACHINIST

i agree but thats what they are saying on CP web site

or i mis under stood

Posted by: spanky101

haha yah, im gonna call bs on that one... anyone wanna donate their quad for testing?

Posted by: THEMACHINIST

ive send them a email last nigth to know if its what they are saying so i will have news later on the week and will see but like you i'm going to say who wants to give a try

Posted by: bwamos

It's possible.. it is a large bor w/ a short stroke. Lends to being able to run a bit more compression. I'd be worried about the extra heat though. Seems to be one point where the DS needs a little aftermarket.

Posted by: Dale512

The 250F Dirtbikes run nearly 13:1 compression ratio on pump. I think KTM actually runs 13.8:1 on their 250.

Posted by: jeepeater347

I ran 13:1 in my 450r for years on pump gas with no problems.

Posted by: ScottB125

Your cam also has alot to do with being able to run pump gas. There is static compression, which is what everyone is referring to and there is dynamic compression. This takes into account the cam timing. DCR is what really matters.