1920 Harley Davidson Sport Twin

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Olive Green Harley Davidson Sport Twin, model designation 'WJ'. Flat twin engine, 584cc, with three-speed transmission featuring sliding-gear operation. The 1920 WJ model introduced electric lighting (rather than acetylene). The Sport models also featured a fully enclosed drive chain and the outside fly-wheel was built up from pressed steel discs and completely enclosed by a guard, aimed to protect clothes of the rider from water, mud, and sand. This example was restored with a 1923 Engine (no. 23WJ1421) and the frame of a 1920 W model.


The Harley-Davidson marque is one of the most recognisable brands of motorcycles, immortalised on the silver screen in iconic films such as Terminator 2, Every Which Way But Loose and of course the 1969 classic Easy Rider.

Founded in Milwaukee, Wisconsin, USA during the first decade of the 20th century, Harley-Davidson was one of two major American motorcycle manufacturers to survive the Great Depression. The company also survived a period of poor quality control and competition from Japanese manufacturers in the 1970s. The company sells today only heavyweight motorcycles over 700cc, designed for cruising on highways. Harley-Davidson motorcycles, or "Harleys", are noted for the tradition of heavy customization that gave rise to the chopper style of motorcycle. Most current Harley-Davidson motorcycles reflect the styles of the classic Harley designs. Attempts to establish itself in the light motorcycle market have met with little success and largely been abandoned since the 1978 sale of its Italian Aermacchi subsidiary. Harley-Davidson sustains a large brand community which keeps active through clubs, events, and a museum. Licensing of the Harley-Davidson brand and logo accounted for $40 million (0.8%) of the company's net revenue in 2010.

In mid-1919 Harley Davidson abandoned the classic v-twin engine model and released the middleweight 584cc Sport model. Harley-Davidson's intention in introducing a new middleweight model was to increase the size of the motorcycle market by appealing to new riders with an entry-level product and capitalise on the growing European trend of flat-twin engines. The motor was a horizontally opposed side-valve twin, patterned after the British made Douglas motorcycle. Combined with its high price and lack of power it proved unpopular compared to its faster rival - the Indian Scout. The Sport Twin was one of Harley-Davidson's least successful early models and it was withdrawn in 1923.

The model in the National Motor Museum collection was fully restored by National Motor Museum staff with assistance from marque experts.


This motorcycle is a rare example of an American made flat twin engine produced by Harley-Davidson for only four years, before the company rationalised it's production to V-twin engines for which the company is renowned.

National Motor Museum Collection


Hello,I have seen your Harleys Sport twin . I have also  a Harley sport twin from 1920 . My Harley needs restauration . Can you help me with information about the engine. For instanse a drawing from the engine will help me rebulding the engineHans Bokhove from te Netherlands
Hello HansWe suggest that you contact the Harley Davidson Museum in the US for this info.http://www.harley-davidson.com/content/h-d/en_US/home/museum/explore/archives.html

Thanks for the information


Hans  I also have Sport Twin and ride it. Look on Antique Motorcycle Club of America forum (AMCA Forum) which will put you in touch with owners world wide and info and photos

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