compression

[YUNGGUNNAZ]

what kind of compression ratio's are you guys running?what type of riding are you doing with those #'s.

[KXcam22]

Sorry, I have no idea what my compression is, but my squish clearance is set at almost the minimum, which would make it a touch higher than stock. Nice bottom end for tight trails and single track.  If I was ice racing or supermoto I might want to reduce the compression a touch to help the engine rev out (while keeping the squish clearance at minimum).  I am not sure what works best for sand drags (gowen would know).  With a powervalve, the compression ratio is dynamic and decreases as the power valve raises the roof of the exhaust port. Cam.

[YUNGGUNNAZ]

cam,hence the high/low specs. given by factory machines with powervalves.curious because of air cooled cr i put together has 214 psi.and a yz 490 had 220 psi.both run very good.the red machine has record in 300ft.my 89 k5 has 240 psi.bike has lost 6 mph in 300 ft. two races in a row with only top end  rebuild.maybe too much comp.