Aerocycle

Posted Mon May 15, 2006 in Motorcycling

V-twin engines—the type that power most cruisers—are a portion of an old, old design… the radial engine. Radial engines were used in early aircraft and are characterized by a series of cylinders arrayed radially about the crankshaft. They produce substantial amounts of torque.

A side-effect of this torque is that early single-engined aircraft turned much better in one direction than the other. This lead to some very interesting aerial maneuvers.

Unfortunately, the “slicing” of a radial-engine into two cylinders leads to a basic imbalance in the engine. Hence my term for v-twins—“shakers.” Significant engineering is required to reduce vibration from an essentially unbalanced system. It’s one of the reasons I prefer BMW boxer-twins, which are inherently balanced (and much smoother running).

The man in the image has circumvented the balance problem by using the entire radial engine. That’s one way to solve the problem.