1955 Vincent 998cc Black Prince Project

Frame no. Upper: RD12894B/F, Rear: RD12794B/F Engine no. F10AB/2B/10994

• Matching upper frame and engine numbers
• Last models made by Vincent
• Found in a dry warehouse

Ever since the Series-A's arrival in 1937, the Vincent v-twin had been synonymous with design innovation, engineering excellence and superlative high performance. In September 1955 when it was revealed that production of the Stevenage-built machines would cease, the news stunned the motorcycling world. It had been decided that the firm's future lay in more profitable lines of manufacture, and just 100 more of the fabulous v-twins would be completed. By the time its demise was announced, Vincent's final twin - the Series-D - had been in production for just six months.
It had been Philip Vincent's belief that provision of ample weather protection combined with enclosure of engine and gearbox, would make the Vincent Series-D the ultimate 'gentleman's motorcycle' and to reflect this change of emphasis the enclosed Rapide and Black Shadow were known as Black Knight and Black Prince respectively. In actuality, delayed delivery of the fiberglass panels - plus continuing demand for traditionally styled models - resulted in over half the production leaving the Stevenage factory in naked form.

Other Series-D innovations included a new frame and rear suspension; a steel tube replaced the original fabricated upper member/oil tank while the paired spring boxes gave way to a single hydraulic coil-spring/damper unit offering a generous seven inches of suspension travel. In place of the integral oil reservoir there was a separate tank beneath the seat. The user-friendly hand-operated center stand was a welcome addition, and there were many improvements to the peerless v-twin engine including coil ignition for easier starting and Amal Monobloc carburetors. Sadly though, the Shadow's magnificent 5 inch-diameter Smiths speedometer had been replaced by a standard 3-inch unit.

Notwithstanding the fact that, as far as Philip Vincent was concerned, the Series-D was his finest design, the motorcycle-buying public greeted the innovative new models with suspicion. The appeal of the Vincent, and the Black Shadow in particular, lay in its ability to out-perform just about every other vehicle on the road, and in the early post-war years there was nothing to compare with it. This was a time when the average family saloon was barely capable of reaching 70mph, and not until the advent of Jaguar's XK120 was there a production sports car that could live with the thundering Stevenage v-twins. Its creator's vision of the Series-D as a two-wheeled Grande Routiere just did not conform to the public's perception of the Vincent as the ultimate sports motorcycle. The firm lost money on every machine made, and when production ceased in December 1955 only 460 Series-D v-twins had been built, some 200 of which were enclosed models like the example offered here.

From a collection of Vincent motorcycles found after 30 years in a dry warehouse in Chicagoland, this Black Prince – last registered in Iowa in 1960 - is disassembled. Now a project bike with no guarantees as to completeness or originality, however the seller does state that the engine and upper frame number are matching according to VOC records. The accompanying photographs catalog the components.