Vincent Black Prince Vincent Black Prince The Vincent Black Prince was a British motorcycle made between 1954 and 1955 by Vincent Motorcycles. A year before the factory closed in 1955, Vincent produced the enclosed range of Vincent Black Knight and Black Prince. Philip Vincent described it as a "two-wheeled Bentley", and the enclosed Vincents attracted a lot of attention at the November 1954 Earls Court show. Quality problems with early production of the glass-fibre mouldings necessitated a replacement supplier causing delays. The last Black Prince left the Vincent production line on Friday, 16 December 1955. Falling sales of the Series C Vincent motorcycles
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