Hi Rob,We are not big motorcycle riders here in the Physics Department but, fortunately, I have a nephew who is an airplane mechanic and rides a souped up Ducati. Here is what he says:LeeH"Hard for me to say without seeing it in person but here are some possibilities.
If indeed the area in question is where wheel weights were it could be some
stubborn lead deposits. Some very careful razor blade action should tell the tale.
Next step is to try some Happich Semichrome polish which is a little more
aggressive than the Never Dull. It's cheap and even if not enough for this
believe me, you'll find more uses for it.
Next would be to try some #0000 and if that is too wimpy some #000 steel
wool but no more coarse than that and use some kerosene or WD-40 while at
it. Hopefully the tires are off and a little practice on the tire side between the
beads is possible.
All of this by hand, no power anything unless versed in the art of not ruining
things with power buffers, Dremals etc. Chrome of this vintage on bikes runs
the gamut from at best OK to a sad joke depending upon many variables.
Hope this helps,
David Wyatt "
Another thought- I'm not sure it matters for the treatment, but for diagnosis you could easily check for lead with a lead-test kit available in most hardware stores of online. There's also a suggestion here
http://www.bae.ncsu.edu/programs/extension/publicat/wqwm/he397.html that manganese deposits can look like that, and a recommendation for easy removal./ mbw
(published on 02/18/2012)