I've had excellent results from Maxima SC1
I wash my bike with simple Green then detail the black metal parts with this stuff. Makes the whole bike look new and shiny. Smells good too.

SC1
Silicone Detailer
Contains no CFC's!
High gloss SC1 Clear Coat is specifically formulated for the Powersports industry. SC1 coats plastic, fiberglass and painted surfaces. Makes the clean up process easier – excellent for use on M/C and ATV fenders to prevent mud and dirt from adhering to plastic. Sc1 dries completely and is water resistant, leaving a long lasting luster without attracting dirt and dust.
Features
Fresh Clean Scent
Restores factory shine and color
Leaves a dry, long lasting luster