c1920 Harley-Davidson 20F 1000cc Motorcycle

Description

The V-twin and Harley-Davidson are inextricably linked, with the earliest prototype appearing at the Chicago Motorcycle Show of 1907 - just four years after the first American V-twin, the Curtiss, was made. Going on sale in 1909, the Model 5-D used as an F-head design of 45-degrees, with inlet-over-exhaust valve layout. With the early single-speed belt-driven twins proving somewhat unreliable, sales were slow and it took a heavily revised version in 1911 to convince the public of the V-twin's merits. A new frame was introduced in 1912, along with a free-wheel hub and a 61-inch (1000cc) version of the engine, with chain final drive, roller and ball crankshaft bearings and more exotic alloy was used for various engine components. Although basic in terms of equipment, it was possible to order an optional Acetylene lighting kit and alongside the solo motorcycle, Harley built the ?Forecar? with a front-mounted luggage box for tradesmen. For 1914 a complex new two-speed hub featuring five bevel gears was announced and production rose accordingly - in 1913 the twins outsold the single Harley for the first time - and within twelve months a more conventional three-speed gearbox had been adopted. For 1920, the model range consisted of the Model 20F and sidecar Model 20FS, while the Model 20J (and JS sidecar) came with electrical equipment. The original Harley-Davidson V-twin underwent two decades of almost constant evolution before being discontinued in 1929 and, such was the pace of change, the last of the breed bore little resemblance to the original Model D of 1909.