Clockwise from top left: William S. Harley, William A. Davidson, Walter Davidson, Sr., Arthur Davidson In 1901, William S. Harley, age 21, drew up plans for a small engine with a displacement of 7.07 cubic inches (116 cc) and four-inch (102 mm) flywheels. The engine was designed for use in a regular pedal-bicycle frame. Over the next two [More]