I recently rebuilt my engine and installed new piston and gaskets and it ran fine. I was idleling the engine while warming it up and it just stopped dead. Tried to start it again and it wouldnt start. So I checked the plug and it was black and wet. So I figured that it was flooded so I let the bike sit and tried starting it again with the choke off, still didnt work. The only thing I do get out of the bike is a series of back fires and thats all. I was thinking since all of the sudden it stopped running maybe I changed something before hand that is keeping it from running now. The only thing I did prior to this is tighten up the exhaust at the port where I noticed exhaust leaking out.