I have a BMX 150cc Atv and was curious what the compression should be? I have about 3 1/2 hours on it right now. I tested it and the compression is around 100 psi right now. I don't believe the engine is broke in completely yet, so will the compression get better the longer I use it? Also, does valve adjustment affect compression at all, because I think the valves are already out of adjustment. Thanks for the help.

 

Thats about right for that motor.

 

I figured it out. I wasn't holding the throttle open when I tested it. I am actually getting 150 psi now.