The Vincent Comet had frame similar in layout to the V-twin Vincent Black Shadow which included Vincent’s proprietary cantilever rear suspension and Vincent’s Girdraulic forks up front. And, like the big V-twins, the engine was a stressed member of the frame, eliminating the need for front downtubes and an engine cradle. This saved weight and mass, and helped ‘the little Vincent’ punch well above its weight class.
COMET ENGINE DESIGN
The 1950 Vincent Comet engine was an air-cooled 499cc OHV single with its camshaft set high in the crankcases. Both the cylinder block and cylinder head were made of aluminum alloy with a cast iron cylinder liner. The compression ratio was 7.3:1. These engines included a very unique valve arrangement with two valve guides on each valve with the forked rocker arms acting on that portion of the valves that laid between the two guides. This gave the valves more lateral support and a much straighter path. The Comet single served as the basis for the V-twin engine in the Vincent Black Shadow, they just doubled everything. The gearbox was a Burman BAP 4-speed, all set in a unit-construction case.