[Purdy Swoft]

I guess it depends on how much bounce. I have found that weak brush springs or an out of round commutator will cause the needle to bounce. Sometimes bounce can be caused by brushes not properly fitted to the commutator. In some cases I have reached in and held pressure on the brush while the engine is running and let the brushes wear in to the commutator, rather than disassembling the generator that somebody else has worked on. This practice can be dangerious if your finger gets caught up in the generator. I am always careful. Using a screwdriver to hold pressure on the brush can cost you an armature if it slips and cuts the wires where they enter the segments.