I have an 01 426. Has run fine for 40+ hrs. On my last ride it started to hesitate when I hammered the throttle. It got so bad it stalled several times. It has also started to backfire real bad and won't idle. When I set the idle and then give it gas the idle will not come back down for 20+ seconds and then may die. Here is what I have done: completely disassembled and cleaned carb 3 times, changed plug, tested for vacuum leak(by spraying cleaner around carb and boots), re-adjusted float, changed needle, main and fuel screw to all kinds of variations. Nothing helps. I plan to check the timing tomorrow. I have reached the end of what I know. Any suggestions, do I check the TPS or CDI and if so, how. I appreciate your help!!!!