Thanks nimadd. At least we know a 110cc quad runs at 120 PSI. But I think this also suggests that camshaft is timed correctly, since a camshaft that is off a tooth must surely affect the compression reading.

Sometimes I'm able to help with quad problems. Other times I am a student learning from others such as yourself.

 

Thanks LunnEdwards; I'm just returning the favor. I've learned a lot from reading what you post. I'm still pretty new to quads but I've got years of messing with every thing from 2 stroke RC planes to big block V8's.

FYI I checked my sons 110 compression again this time wet. It ran up to 132.

I just can't get past the fuel blowing out of the carb while it's running. Is it spitting out droplets or more of a mist? hrndz69 are you checking compression wet (just after running the engine) or dry (after it's been sitting a day or so) if wet then it's low.

Another timing check is to take a peace of paper and hold it at the muffler outlet. If the paper gets blown away then sucked up to the muffler you've got a valve timing problem.

 

make sure exhaust pipe is not plugged at all,turn up idle ,or spray wd 40 around gaskets if idle goes up then air leak