1920 ABC 398cc

Registration no. DS 7755 Frame no. 1111 Engine no. 1111

Designed by Granville Bradshaw and produced by the Sopwith Aircraft Company, the ABC drew heavily on its designer's wartime experience in the development of air-cooled aero engines. A ground-breaking design, the ABC engine was a 398cc overhead-valve flat twin with integral four-speed gearbox. Legend has it that the power unit was designed in under three weeks, but Bradshaw did not stop there, going on to pen the duplex loop frame and sprung front and rear forks that marked out the ABC as one of the most advanced motorcycles of its day. It was fast too, J L E Emerson breaking the one-hour record twice at Brooklands, the second time at an average speed of 70.44mph, a feat that necessitated exceeding 80mph on occasions. Despite these successes, this promising design was hamstrung by production difficulties and price increases, only 3,000-or-so being made up to 1921 when the Sopwith factory ceased manufacture, though production of a modified version was continued by Gnome & Rhone in France. Although it is not known for how long the vendor has owned this ABC, it could have been acquired as long ago as the 1970s. Unused for a number of years, the machine appears sound; nevertheless, sympathetic re-commissioning and the customary safety checks are advised before returning it to the road. Offered with some photocopied technical literature and a V5C.