Timing '68 750

I decided to do some tune-up work this morning. When I got everything done and was doing the timing with a timing light, the timing mark is wandering constantly. I can't get an accurate or steady reading, no matter what the RPM is. The timing light is hooked up to a spare 12V battery. The bike has a Boyer ignition. The bike runs really sweet, but I've never encountered a bike where the mark keeps moving around. Any ideas?

First thing I would suspect is the timing chain. But then I have never seen my 69 with a solid steady strobed timing mark, but it only wanders around maybe 1-2°.

Dave
69S

Hey Dave. That's kind of what I would expect. This is probably 6-8 degrees. Hate to fiddle with it as it is running so nice, but may have to get a little deeper.

Could be a worn bush in the stator that is making the timing light to jump, if the bike is running good why bother with the timing at all , when things are running good leave things the way they are...

Ashley