I had the same problem vith vibration on my 94 DR and went in to tighten/adjust the balancer chain. It was very loose and out of alignment. In order to line everything up the way it's shown in the manual I had to turn the engine using the rotor bolt. I got everything back together but now the engine won't turn over. It's as if the engine was locked up. Is it possible that I messed up the timing by turning the engine by hand? Other than making sure the problem was not electrical I haven't really tried anything. Any suggestions would be great....Thanks.