Hey another problem wit my 250r

[Manny55]

Hey its manny i have another problem wit my 250r. First it was the rear axle and the sprocket hub and the sprocket then it was the carburator which i just fixed 4 days ago and now i have no clue wuts wrong wit it next. Some times I can start it up but then it just starts to die and sometimes it backfires when i try to start but then it dies. I have no clue wut could be wrong becuz i just fixed carb its fine it could be the coiler but sometimes i can start it and then it just dies. If u might know wut is wrong plzzz reply back or maybe i need like a tune up lol i dont know.

Manny