Hi, I am new to the forums and I recently bought an 05 Raptor 350RT. When I bought the atv the guy had just put a new White Brothers MX4 exhaust on it. He also told me that he re-jetted the carb when he put the new exhaust on, otherwise the atv is stock. When I start it up cold, the carburator backfires and the atv stalls. This is only on the first couple of tries, once its warm it wont stall but sometimes i hear the carb backfire when I let off the throttle. I have searched and I found that I am probably running to lean? I just wanted to check with you guys before I mess with anything to see if you guys have ne other ideas? Thanks a lot in advance!