spike400 Posted November 2, 2015 I have a 2008 yz125 with the athena stock bore kit. Was wondering if anyone knew what the compression should be at roughly. It has about 3 hours on it since rebuild and seems to be getting way to easy to kick over. Share this post Link to post Share on other sites
mlatour Posted November 2, 2015 If it's any reference, my stock OEM cylinder 2010 YZ125 gets 180-185psi when freshly rebuilt / broken-in. Share this post Link to post Share on other sites
qwert321 Posted November 2, 2015 2500ft and every yz125 I have owned was between 150psi &160psi. Every compression gauge is different and altitude is also suppose to affect readings. Share this post Link to post Share on other sites
qwert321 Posted November 2, 2015 Yz125 are quite easy to kick over. Share this post Link to post Share on other sites
spike400 Posted November 2, 2015 When it was cold I got 125 psi Share this post Link to post Share on other sites
spike400 Posted November 2, 2015 Cause my 250 puts out 175-180 psi Share this post Link to post Share on other sites
mlatour Posted November 2, 2015 (edited) A fresh 250 should be in the 200-220psi range, try another gauge perhaps yours is out of calibration. Also change your procedure: check with the engine warmed up to temp, hold the throttle wide open while kicking, about 10 kicks to get highest reading. Edited November 2, 2015 by mlatour Share this post Link to post Share on other sites
spike400 Posted November 2, 2015 Thanks for tip. I'm new to the game. The 250 is all oem as far as I know I got it used with 23 hours on the clock it's a 2013 and just trying to figure out were they are at. I'll be doing that tonight on both of them. Thanks for the help guys. Share this post Link to post Share on other sites
