How to Polish an Aluminum Motorcycle Crankcase
- 1). Wipe down the crankcase with a cloth and mild soap to remove as much dirt as you can.
- 2). Run the crankcase through a normal cycle on your dishwasher and let it dry thoroughly.
- 3). Apply a small amount of metal polish to a microfiber cloth. Rub the polish onto the crankcase in small concentric circles and work your way all around.
- 4). Add more polish to the cloth as you use it up, until the surface of the case is fully covered with polish.
- 5). Buff the polish to a shine with a clean portion of the microfiber cloth until the crankcase is clean and shiny.
Source...