I was riding a 2nd gear wheelie when the bike started doing what I call the "boogie woogie" It just started wobbling back and forth. I had to set it down as the wobbling was getting worse and I was out of gear. When the front came down it went into a tank slapper from hell. I rode that for like, a second and a half and then it was sparks and me sliding down the road. So what caused the bike to start wobbling while on the rear wheel? Would a fairly worn back tire do this? It hadn't done that before.