I have had a 2000 Grizzly 600 since new. Don't ride it much, but use it to run around the pits at our boat races. Last year, it started this issue that we have yet to resolve. It will POP while at idle, and blow the carburetor off. Took it to a Yamaha dealer, they adjusted valves, tuned it up, and it worked for a day or two, and then POP, and blows the carb off. Just a pain, to pull covers, and reinstall carb. This issue has been going on way to long. About ready to sell this thing, and buy a new one. Any help with this issue would be GREATLY APPRECIATED. Thanks!!!