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- Written by Carole Nash Editor
- Created: 24 June 2008
Few would argue with Steve Berry’s claim that the Black Shadow was the best British V-Twin ever, nor the suggestion that it lay the ground for the Superbikes that were to follow decades later.
The 1948 love-child of engineers Phil Vincent and Phil Irving, the Shadow´s raw, brutish 998cc air-cooled OHC engine kicked out 55bhp at 5,700rpm to deliver a top speed of 125mph and become, as Vincent´s advertising proudly proclaimed, "The World´s Fastest Production Motorcycle".
Ingenious engineering did away with a traditional tubular frame as the muscular engine and four-speed gearbox became the bike´s backbone, linking the steering head and rear-sub-frame, the latter equipped with cantilevered suspension to deliver a remarkably smooth, responsive ride.
Whilst the Shadow set the pulses of many red-blooded riders racing, at over £400 it remained for many just a fantasy, a fact which would lead to it and Vincent´s demise in the mid-Fifties.
Jim Reynolds recalls a British legend - the Vincent Black Shadow
The high price this model fetches at auction reflects its stature as one of the very best of British bikes. Introduced in February 1948, the Black Shadow was an uprated version of the established Rapide 998cc vee-twin, with higher compression ratio and bigger Amal carburetters. That was enough to produce 55bhp at 5,700rpm and gave it a top speed over 120mph, in an age when sporting 500’s struggled to top 90 on the 72 octane petrol available - even racing bikes like the Manx Norton couldn’t couldn’t match the performance of the new sensation. Designed by the legendary Australian Phil Irving, the Shadow was head and shoulders above the rest.
A breakthrough in design, it used the engine as a chassis member, with a steel box section top tube carrying the engine oil, while the cantilever rear suspension was pivoted on a lug at the back of the gearbox that was in unit with the engine. Twin 7-inch (178mm) front brakes with ribbed drums provided stopping power to match the performance and the proud owner could check his speed with a quick glance at the 5-inch (127mm) speedometer mounted above the steering head.
The transmission to handle this level of power had to be something special, and Irving’s ingenious answer was a triplex primary chain to a clutch that initially took up power like a conventional unit. Once the torque rose, shoes servoed against the clutch drum in the manner of a brake.
The alloy engine was finished in black, like the cycle parts. The tank too was enamelled black, relieved only by a single gold line and the Vincent scroll-like logo. The muguards and many cycle parts were alloy, to help keep the weight down to 458 pounds (208kg).
An uprating in 1950 included the adoption of Vincent’s own `Girdraulic’ front forks and hydraulic damping at the rear, for the Series C version, widely regarded as the ultimate version of the model.
You have to ride Vincent’s twin to realise what a unique high-speed carriage it is. The 50 degree vee-twin engine is smooth and unhurried, giving no impression of speed; at 60mph the engine is only turning over at 2,700 rpm, so at little more than 5,000 rpm in the top of its four gears you are almost guaranteed to lose your licence if you’re caught. Many riders have been lulled into trouble by the Vincent’s unhurried feeling, which probably explains why the speedometer is mounted in the unsuspecting rider’s line of sight.
The Black Shadow has always been a machine for the connoisseur with riding ability. In 1950 it cost £425, when Triumph’s fast selling 650cc `Thunderbird’ was only £194, yet the factory in Stevenage, Hertfordshire, was struggling to keep up with demand. They were in financial trouble, operating under a receiver who did believe in the product and invested in machine tools. But a revolutionary fully enclosed 1955 version failed to please the public and sales slowed until production stopped in 1956.
The Shadow remains a giant amongst motorcycles, a tribute to a factory that was only interested in building the best.
Get Carole Nash motorbike insurance for the Vincent Black Shadow.
Engine 50 degree vee-twin in alloy, 84mm bore x 90mm stroke
Claimed power (bhp) 55 @ 5700 rpm
Compression ratio 7.3 to 1 Twin Amal 32mm 279 carburetters
Transmission Triplex primary chain, four-speed gearbox, single chain to rear wheel
Two 7-inch (178mm) single leading shoe front brakes, single at rear
Brampton girder forks in 1948, with Vincent Girdraulic optional from 1950
Cantilever rear suspension; upper frame steel box unit; engine is stressed member.
Top speed 125mph (201 km/hr)
fuel consumption 50-55 mpg
standing start 440 yards (400m) 15.0 seconds @ 90mph terminal speed
Current price £10,00 to 12,000 for a good example