Vincent Black Shadow Vincent Black Shadow Motorcycles produced by Vincent H·R·D at their factory in Stevenage, Hertfordshire, England were renowned for their design innovation, engineering excellence and high performance. Already advertising their existing 110 mph Rapide machine as ‘The world’s fastest production motorcycle’, in February 1948 the distinctive Vincent Black Shadow was announced with a top speed of 125 mph. Built in three different Series over the course of its life, the line continued until 1955, after which the company stopped all motorcycle production. The Black Shadow uses a version of the air-cooled four-stroke 50° V-twin engine that powers the Vincent Rapide. Bore
Vincent Black Shadow engine's ports. Early Black Shadows have a third inner valve spring not shared with the Rapide, but this feature was dropped from later bikes. Due to the low-octane 'Pool' petrol that was all that was available in the early post-war years, bikes of the period could have only low compression ratios. Although the prototype Black Shadow was built with a compression ratio lower than the Rapide's nominal 6.8:1, production Shadows have a ratio of 7.3:1 due to having different pistons from the Rapide, although still supplied by Specialloid. The Black Shadows have different carburettors than the Rapides, with Series B