Ok this is my very first post, My raptor that I just bought from a guy like 2 months ago had been starting fine, one day I go to the garage to start it and all it does is pop and back fire, eventually tore the carbs down and cleaned them, nothing real bad, now that I put it back together it turns over but wont stay running, I actually stayed on the gas and it stayed running, as soon as I got off the gas it kills, sometime it will stay on, sometimes it wont, any suggestions?