By 1905, the focus was on power, and manufacturers begin to beef up their engines. That year, Hedstrom produced a machine boasting a 500 cc twin engine that featured twist -grip control for the throttle and ignition. That same year saw the development of "free engine" devices, which eased the starting and launching of a machine, and variable gears, which eased use on hills and at slow speeds. Chain drive followed, and the stage was set for production of the motorcycle that is currently in use.

     William Harley and Arthur Davidson were students in Milwaukee when they built their first motorcycle on a borrowed lathe from patterns they had made. Davidson's older brothers, both toolmakers, assisted, as did Ole Evinrude, who later became famous as a designer and producer of outboard motor boat engines.

    The 1950s were regarded as a "golden age" for the motorcycle, with its use being popularized by such prominent figures in popular culture as James Dean in his movie "Rebel Without a Cause." The United States and Europe dominated the motorcycle industry through 1960, at which time Japanese manufacturers, including Honda, Yamaha, Suzuki and Kawasaki, rose to a prominence they maintain to this day.