It should have......12.0:1
hey there smartie pants thats the compression ratio. not the compression he wll see on a compression test. it would be in psi. i would firgure around 120psi but thats just my guess.
divide the PSI number from the compression test by 15 and that is your compression ratio. that will get you close.
I don't know about that. That'll work when it's new, but after it wears and the compression goes down, that won't really work anymore. The ratio will always be the same. That's the volume of the cylinder and head when the piston is at BDC, compared to the volume when it's at TDC. How much compression a motor has changes as it wears or gets rebuilt. Go to
www.thumpertalk.com though for an answer. 120 seems low to me? 2 stroke MX bikes will see 200 often. I'm not sure if 4 strokes just don't need that kinda compression to run awesome.
