I recently experienced the same problem (see subject: Rebuild now vibration). I never had any vibration before the rebuild, and then after an hours ride it started like someone turned on a switch. My hands were tingling after just a few minutes. I was ready to completely tear apart the engine. But, I got some good advise from some of the guys here, and I kinda snuck up on it instead. Checked one thing at a time. Mounting bolts, etc. I discovered that the bronze bushing the clutch basket rides on was worn. I might have missed it during the rebuild, or maybe it went after the rebuild. I'll put a new one in and see if that fixes it. I may still have to go deeper. I hope not. I guess my advice is: the best approach is to check things systematically until you find the problem, then test it. You still may have to go deep into the engine. But maybe not if you find something pretty obvious like I did. If you didn't have the vibration previously, and now you do, something has changed, and should be looked into. These bikes seem to be rough on bearings, bushings, etc. When I did my rebuild I had to replace a lot of bearings. It had approx 200 hours at that time. Good luck.