Well like always my initial diagnosis was WAY OFF!..lol....A few years ago (maybe less, maybe more, at this age who knows!) I dropped the bike when dodging a car changing lanes, and apparently the rear fender had also sustained damage that I didn't catch when assessing the damages for insurance purposes. It appears that three out of the four hold down screw mounts for the rear fender had been damaged and only one bracket was keeping the fender in place. It finally gave way and for that day only the fender was just riding and bouncing off the rear tire. The way I figured it out it was not a mechanical/fuel issue was while driving 65 mph and hearing the popping I shut off the motor to coast and the popping never stopped until the bike got down below 35 mph. I guess I should be glad the fender didn't jam up into the spoke of the rear tire and cause a major accident. So now after looking at kymcoparts.com I located all the replacement parts needed to fix it and it's all under $60 total. But now I question the need for that rear fender since I never ride in the rain. Thanks to you guys for input. But we're back on the road...minus a part or two but hey, we be ridin!