Hello. I go by the name of Slider, my wife and I live in a small village in the jungle of central america.where we have no access to a mototcycle shop, and I am in need of some help with my Yam xt250.Bike starts and runs great, but when I let off the gas it backfires like a popcorn popper.I have cleaned the fuel system and reset the valves. Now what? 2010 xt250 thank you. Slider