was wound up. In 2004, around 1,000 Brough Superior motorcycles still existed, maintained by enthusiasts. Brough Superior motorcycles Early models include the Brough Superior Mark I Sidevalve, Mark I Overhead, Mark II Standard and Mark II Sports. Early to mid manufacture included the Overhead 500, 680 S.V. Junior, and 750 Side Valve, but these were not popular and were dropped from production. The following four models represent the bulk of manufacture. Most were custom built to order and many variations were made: The SS100 (Super Sports), powered by J.A.P. (J. A. Prestwich of Tottenham) or Matchless 1000 cc overhead valve V-twin engines. Approximately 383 were manufactured from 1924 to 1940. The SS80 (Super Sports), powered by J.A.P. or Matchless 1,000 cc sidevalve V-twin engines. Approximately 1,086 were manufactured from 1922 to 1940. The 680 O.H.V., powered by J.A.P. 680 cc overhead valve V-twin. Approximately 547 were manufactured from 1926 to 1936. The 11.50, powered by J.A.P 1096 cc sidevalve 60° V-twin engines. These were primarily designed for sidecar and police use. Approximately 308 were manufactured from 1933 to 1940. The model name refers to the horsepower rating of the engine, 11 RAC (Royal Automobile Club), . In reality these engines produced under 30 bhp (under 22 kW). Tax horsepower ratings were required by manufactures for tax purposes. RAC HP equals the piston diameter squared times the number of cylinders divided by 2.5. Brough Superior produced many other experimental, show, and racing models. These include: Golden Dream. This was powered by a vertically stacked twin crankshaft opposed four cylinder engine. George Brough called this a "flat vertical" engine, which used a shaft final drive. The bike was finished in gold paint for the London Motorcycle Show. It was unveiled at the motorcycle show at Earls Court in 1938. Brough Superior Austin Four or BS4. This bike was powered by a modified Austin 7 automobile engine and transmission. As the prop-shaft of the automotive transmission emerged in the center of the motorcycle's driveline, George Brough used two rear wheels mounted to a central, cast final drive unit. As the rear wheels were within 24" of each other, the Brough Superior 3-wheeler was legally considered a 'motorcycle' in the UK. It remains the only motorcycle in history to use this configuration. The Brough-Austin Four was intended for sidecar use, although one was ordered without a sidecar by journalist Hubert Chantry, who had borrowed