How many times has this happened ?
Will it happen every time in a predictable way ?
I very occasionally get a 'bang from the back end' , and to date have put it down to slop in the drive train being suddenly taken up , with no after effects or detectable damage. It usually happens to me when coasting in a low gear , then suddenly accelerating.
I think it sounds louder than one would expect from drive component due to the sound echoing round the body shell and due to the shape being focused on the cockpit area. I have grown to ignore it , after checking everything is screwed down tight.
I have recently seen a Harley belt that had been used in drag racing and suffered catastrophic damage as a result , with some belt slipping taking place. A number of teeth had been partially ripped off the belt , others were obviously in a bad way. So my gut feel is if belt slipping happens often , the belt will visually be in a bad way , which I have never see to date on an M3W.
