czapa Posted April 11, 2010 hi there trying to find out what compression is good on cylinder? i got 120 psi with brand new piston , is that okay? thanks Share this post Link to post Share on other sites
maxamillion125 Posted April 12, 2010 I have 135 psi on my 05 125sx. I've been told that is fairly low. Your looking some where in the range of 120 to 180. But as long as it starts on the first couple kicks you should be good. Share this post Link to post Share on other sites
Crude Posted April 12, 2010 My new 09 with 1/2 hour on it I got 150psi, got the head shaved at Munn's Racing and only gained 10psi, thought It would be higher with a shaved head. My 250 with a SX head had 190 psi. Share this post Link to post Share on other sites
fender bender 59 Posted April 12, 2010 hi there trying to find out what compression is good on cylinder? i got 120 psi with brand new piston , is that okay? thanks ARE you sure your doing it right??? not to piss you off....but a lot of people don't.... Share this post Link to post Share on other sites
czapa Posted April 12, 2010 i 99% i put it all togerther right , i did it with the book , I was only kind of afraid of the power valve thing , because i pulled it all apart for cleaning, but then put it back together with the book. Share this post Link to post Share on other sites
NORTEXED Posted April 12, 2010 I'm going to check my son's for frame of reference, since it has new 2 ring piston, and was wondering hot or cold? Share this post Link to post Share on other sites
