Harley-Davidsons are special. Aside from their unique "potato-potato" exhaust note, they stand apart from most motorcycles mainly due to their single-pin crankshaft design and their belt final drives.

A chain is the most common form of drive on two wheels — not only motorcycles, but bicycles, too. This is not the only way to transmit power to the wheel, though. Some bikes use a shaft in the same ...