Alright I was ridin my 250 a while ago and it was running good then all of the sudden stalled and wouldn't start back up. I brought it home and checked it out and realized there was an air leak on the bottom of the crankcase. So i fixed the airleak but the bike still wont start. Im thinking it could be because when there was an air leak it was running really lean and now it needs a new piston and rings? There is not much compression at all and it has good spark and the carb is clean and everything. Would it cause it not to start because of low compression? Thanks for the help.

 

Yep, low compression will stop it from starting.