A 1921 Harley-Davidson 584cc Model WJ Sport Project Engine no. 21WJ2139,
this example consists of a frame, tank and engine, footpedal and retains remnants of its original paintwork. Inspired by the British Douglas, that likewise used a horizontally-opposed, twin-cylinder engine, the Harley-Davidson Model W Sport would prove more popular in Europe than America, where the v-twin engine held sway. The Model W was introduced in 1919 and, like Douglas, Harley set its engine length-ways in the frame. Displacing 584cc, the 6hp twin was installed in a frame of the 'keystone' type, open at the bottom, which used the engine as a stressed element, while other noteworthy features included geared primary drive and a unique type of front fork. Although not overly powerful, the Model W obviously handled well and possessed a decent turn of speed, as evidenced by a number of record-breaking achievements including a new best time for the 'Three Flags' run from Canada to Mexico. Despite these successes the American motorcycling public remained unconvinced of the Model W's virtues and H-D pulled the plug on this promising design after only a few seasons. Production ended in 1923, by which time 9,883 machines had been built, only 60-or-so of which are believed to be on the road today.