While a good coat of wax will help prevent this kind of problem, it's awful hard to get it in all the nooks and crannies. I would recommend something else if you are going to store the bike for several months in a non-humidity environment. Before putting the "clean" bike away, lightly fog the wheels and motor with a coat of WD40. It works great but obviously, don't soak the tires with it.

 

Neverdull or Harley metal polish. PIA, that is why I went to chrome wheels.