dammit

Ive assembled a wonderful motorized bike and managed to figure out pretty much everything to make it work, with a little help from the forum. It runs great and it goes pretty well too, however I've only put 11 miles (as stated by speedo) on it and I've killed two chains already. The first break...

Alright, so in all I'm fairly new to this. I put together my bike, after much struggle I got it to work, and it worked fine for a whole month. Now when I try to start it, release the clutch, it revvs up and then I can start pedaling keeping the engine in idle,throttle works and I can hear it...