There are few more satisfying tasks when restoring a classic motorcycle than polishing the engine cases. In most instances, the cases will look better than new. However, the owner must be sure that the value of the bike will not be diminished by polishing the cases—the original bike may not have had polished cases and a collector will not be impressed with this “update!”
For many buyers of motorcycles, spending time polishing their bike is a pleasure. In the 60s, when polishing the cases on café racers, for instance, became popular, many of the owners would periodically apply various aluminum polishing compounds to the clutch covers on their Triumphs, Nortons and BSAs.
Today more modern classic owners will have their engine cases chrome plated—a process that was difficult and too expensive in the 60s.
Polishing is Simple
Although not strictly original, most restorers of classic motorcycles will typically polish their machines cases. For the most part, polishing aluminum cases is relatively simple, requiring more time than money to accomplish.
For someone intending to restore more than one motorcycle or who has a well equipped workshop, a buffing wheel is essential. These machines, often mounted on a pedestal for easy all round access to the wheels, are relatively inexpensive, costing around $120 for the machine and pedestal. However, it is possible to use a regular hand held drill with a buffing wheel attachment to get a reasonable finish on a case.
Before the polishing process can be begin, the mechanic must remove the cases from the bike and thoroughly clean them inside and out (it is important to clean the inside too as doing this after the cases have been polished can result in scratches from movement inside a wash tank).