I am new to the Venture have only put a few hundred miles on it, I have a vibration that starts about 65 mph and gets worse up to 75 that makes the bike almost buzz like they did 30 years ago is this normal? Mine is a 2006 w/5000 miles on it and the vibe goes away if I pull in the clutch and let it coast so it must be engine or drive train related. I also just switched to straight synthetic oil abut 300 miles ago, this really quieted it down but now I have noticed this vibe beginning and it seems to be rpm related. Any ideas?