i have this bike thats been giving me fits. i cant seem to figure out how to get rid of the backfiring its doing. when it turns on it backfires really bad. Ive cleaned the carb and jets and its still doing it. Also ive changed the plug and put new gas in it. still the same thing. i finally called the guy i bought it from and he told me that the carb prob needed to be rebuilt. He also told me that when i turn it on the choke stays on and that was probably the reason it was backfiring. By the way,when it backfires it shoots fire out the back. Well now i cant turn the bike back on. Any suggestion on what is going on with bike.