Aluminum is a metal component that is both durable and light-weight. Unlike steel, it is rust-resistant and able to withstand the elements. Because of these qualities, it is often used to make motorcycle parts, from trim to engines. Over time, general wear and tear can scratch the surface of the material. That obscures its shiny chrome finish. Fortunately, polishing aluminum engines is a relatively simple project that will leave your bike looking new again.
Protect the carburetor and any electrical components by covering them with plastic sheets. Secure the sheets with tape. You'll want to keep these items from getting wet or damaged during the polishing process.
Apply a small amount of grease cleaner to your steel wool pads. Use them to thoroughly clean the engine. Take your time to ensure all dirt, grease and grime are removed before proceeding.
Use 400 grit sandpaper to sand away any deep scratches or damaged areas. Periodically dip the sandpaper in water as you work so that sanding residue is removed.
Repeat Step 3 using 800 grit sandpaper to further refine the aluminum surface.
Repeat Step 3 using 1500 grit sandpaper. On this round, sand in only one direction using smooth, even strokes.
Apply a bit of metal polish to a soft cloth. Use it to polish the engine by hand. This will leave the engine shiny and clean, and it will also help protect it from future damage.
It may be necessary to use a lower grit sandpaper if you have significant damage or deep scratches on your engine.
Don't start the polish unless you are sure it's going to be a clear day. You don't want to have your work destroyed or interrupted by the weather.