Vincent Black Shadow
Any 1,000cc motorcycle today can hit 150 mph, but the Black Shadow was doing that sixty years ago. It was an exquisite British machine, conceived and designed by engineers to out-handle, out-accelerate, and out-brake every other motorcycle of its time.
Upon graduating college with an engineering degree in 1928, Philip Vincent bought the rights to the troubled H.R.D. (Howard R. Davies) Motorcycle Company, adopting the name Vincent-HRD. His first bikes used British JAP engines in an original frame design which featured his patented cantilever rear suspension. In 1931, Australian-born Phil Irving joined the company, and as chief engineer, co-designed original engines with Vincent. After several successful 500cc single cylinder bikes, their first V-twin motorcycle was the Series A Rapide, introduced in October of 1936. Cylinders were set 47.5 degrees apart, compression was 6.8:1, and a separate, 4-speed gearbox was mounted behind the engine. The under-square 84mm x 90mm bore and stroke displaced 998cc.
Vincent Series B Rapide
Shortly after the second World War, the shorter, lighter, and faster Series B Rapide appeared. The cylinder angle was changed to 50 degrees, and the motor now hung suspended from above as an integral part of the frame, with the front and rear suspension attached to it. A triangulated 6-pint oil tank connected to the top of frame under the gas tank spine. The external 4-speed gearbox was gone; the transmission now sat inside the engine cases.
While other bike manufacturers were changing to hydraulic telescopic forks, both Vincent and Irving believed their girder forks, made from aircraft-quality alloy and hydraulically dampened, to be superior at high speeds. The Vincent's rear suspension, decades ahead of its time, was comprised of a triangular-shaped structure located under the seat. This pivoted rear fork assembly gave excellent high-speed dampening and predated the modern monoshock by thirty years.
At 475 pounds, the Series B Rapide rode on a 56" wheelbase and was capable of 110 mph. Front and rear wheels were detachable without tools, with the back fender hinged for easy access. The rear wheel wore sprockets on both sides to provide quick, alternate gearing. Stopping power was supplied by four brakes, two per wheel. Both brake and shift foot-pedals were adjustable.
The Black Shadow, introduced in 1948, was a faster, super-sports variant of the Rapide. The company's aim was to offer a bike that ran 125 mph without sacrificing low-speed driveability. Increased power was accomplished through use of larger inlet ports, lighter and stronger connecting rods, and high compression. Output was 54-bhp at 5700 rpm. Two Amal carburetors fed the two cylinders finished in black. Heads, crankcase cover, and side covers were also black. A large, easy to read 150-mph speedometer sat upright in the middle of the handlebars.
The Black Lightning was offered as a race version of the Black Shadow. Output was increased by using hotter cams, higher compression ratio, and larger carburetors. Non-essential parts were removed, and lighter-weight alloys replaced steel parts when possible.
Record-Setting Vincent Black Shadow At Bonneville
In 1948, a Black Lightning ran at the Bonneville Salt Flats, breaking the existing class record of 136.183 mph, held by Joe Petrali riding a Harley-Davidson. The Vincent's seat, front fender and front brakes were removed to reduce weight. Stretched out flat on the rear fender, dressed only in a bathing suit and cap to reduce wind resistance, racer Rollie Free set a new world record of 150.313 mph.
Nearly 12,000 Vincent V-twins were built after WW2. Fewer than 1,700 were Black Shadows. Each and every bike produced was hand-built and used the highest quality materials. Bright parts were mostly aluminum or stainless steel, and aluminum-alloy was used when and where it could save weight or make a part stronger. Expensive to produce and not profitable to make in the quantities at which they sold, Vincent Motorcycles ceased production in December of 1955.