I bet its the compression. You need to retorque you're head bolts to factory specs. My 110 did the exact same thing you are explaining...ran excellent one day, wouldn't even try to start the next, it got fire, got gas, got air. I cleaned the carb and everything trying to get it to start and was about to part it out and sell it because of the frustration when a little thought bubble popped into my head. You can't imagine what 1/4 to 1/2 turns of a head bolt can do. It fired up on the first pull and ran better than ever. If it is the head bolts and you have a few threads left on the studs after you get done tightening them down, put a lock nut over the head bolts...this will keep them from backing off as fast. Hope this helps.