I'm (still) restoring a 1983 R100RS. I think the guy before me stored it outside in the snow but that's another set of issues.
The current problem is a voltmeter that hits the maximum voltage peg when I'm at a constant speed (around 4,000 RPM). It spikes up and sometimes gets caught up there. Physically tapping on it brings it down to the more normal 12.8V. Then it'll spike again. I'd say that it spikes about 30% of the time. I'm running an Odyssey battery that's essentially new (~300 miles on it). Interestingly, everything's fine in the mornings when I go to work. It only happens on the way home after its been under its cover (heat issue?).
I suspect the voltage regulator or it could be worn out brushes (it's got about 52,000 miles on it). Last night I cleaned the connections to the voltmeter. Am I hurting anything if I keep running it this way? All the time the bike doesn't skip a beat and seems to run fine. Has anyone else had this sort of problem? This thing's getting to be the money pit and I'm (frankly) tired of putting more money into it - just want to ride. I'm hoping for a single point fix.