So I have a 1998 Yamaha grizzly 600 ran fine before I rebuilt the motor and jetting it. But I had to rebuild it due to it started smoking really bad. I have it put back together and idles but if you try to accelerate it backfires through carb and quits. The valves were adjusted right but other than that I have no clue what to do. It is driving me nuts. If you guys have ideas, please let me know.