Posh Totty: Vincent Black Shadow
This is the daddy of posh totty – the first post-war superbike and the fastest production motorcycle in the world for more than two decades.
In our look at those coffee-table bikes few can afford, we look at Vincent’s racer, the Black Shadow.
The Vincent Black Shadow could crack 125mph. In 1948. Vincent pointed out in their advertising: “This is a fact, not a slogan”, and it took until 1973 and the mighty Kawasaki Z1 to surpass the Black Shadow’s blistering performance. The Vincent dripped with technological innovations and it had that most important of things – presence.
The legend that was Vincent had an inauspicious birth. Motorcycle company
HRD was founded in 1924 by Howard R Davies, who won a Senior TT on a 350 – the only man to have won a TT on his own motorcycle.
The company floundered after just a few years and was bought by Philip C Vincent in 1928. P C Vincent was aged
22, two years into a mechanical science degree at Kings College, Cambridge, and had already patented his cantilever rear suspension system when he paid £450 for HRD.
The company used externally supplied engines from JAP and Rudge until 1935. After a series of embarrassing engine failures in the 1934 TT, Vincent, along with genius designer Philip Irving, came up with their first engine, the 500cc single, in the 1935 Comet. This followed with the 998cc Series A Rapide V-twin in 1936. During the Second World War, Vincent and Irving came up with the Series B Rapide when they weren’t building things for the military, and it was an up-gunned
version of this V-twin that became the Black Shadow.
The Black Shadow was born. There would be three models – B, C and D, with C being most sought-after today. It was developed from the easier-to-live-with Rapide which, at 110mph, was no slouch.
The first Series B Black Shadow used a version of the Rapide’s air-cooled fourstroke 50-degree V-twin engine. The 998-cc V-twin put out 55bhp and weighed 458lb, about as much as middleweight 1970s Japanese four.
Vincent and Irving broke with convention, insisting that the engine casings had a baked-on heat-dispersing black finish rather than polished alloy.
Post-war there were steel shortages, but alloy and stainless were available in considerable quantities, and the Black Shadow used a lot of alloy and a lot of stainless steel.
Stats abound about the Black Shadow. The 55bhp arrived at 5,500rpm, it had 7.3:1 compression ratio pistons, and a pair of one-and-three-quarter inch carbs. There were two overhead valves per cylinder, operated through rocker arms and short pushrods by two gear-driven cams mounted high in the engine’s timing case.
The valves had both upper and lower guides, and the rocker arms were forked at the valve end to operate the valve by pushing on a metal shoulder part way along the length of the stem.
This distributed the effort of forcing the valve down on two sides of the valve stem.
The theory was that this provided balance in the compressing forces, rather than conventional valve operation, which puts all the pressure on the top of the valve stem.
Early Black Shadows had a third inner valve spring which was not shared with the Rapide, but this feature was dropped from later bikes. The pre-war Rapide engine it was developed from had a tangled undergrowth of oil pipe feeds and exposed mechanicals, and the early workshop manual recommended that owners took apart their engines every 1000 miles.
“After a series of third-party engine failures in the 1934 TT, Vincent, along with genius designer Philip Irving, came up with their first engine, the 500cc single in the 1935 Comet. This followed with the 998cc, Series A Rapide V-twin, in 1936.”
The Black Shadow eschewed this plumbers’ nightmare and was a much more modern creation.
The engines were built using the best possible parts from the Rapide assembly line, which were polished inside and out before fitting. The engine was of unit construction with an integral four-speed gearbox that would pull from 30mph in top gear, and it had a two-part clutch; one part with a single pressure plate that transmitted the initial power, while a second section operated in a manner similar to a drum brake. This was to cope with the increase in power as you wound the throttle on.
Vincents were packed with innovations, some of which would take other manufacturers years to catch up with. The top frame tube was the oil tank (see the oil-in-frame Bonneville). The frame, such as it was, came in three sections, with the engine a stressed member (like Ducati’s Desmosedici). The rear mudguard was
hinged on a pivot, meaning you could get the rear wheel off in 90 seconds. That back wheel was reversible, with a drive sprocket on either side, allowing the rider the choice of two final drive gears.
It had the company’s own cantilever rear suspension, later copied by Yamaha in the 1970s. This consisted of vertical parallel triangulated cantilevers that extended on either side of the rear wheel and pivoted at the bottom on the bike’s rear frame, with the top attached to a pair of sprung telescopic shock absorbers.
The Series C had the added benefit of a hydraulic damper. The seat had its own independent shock absorber system. There was a range of brakes available, but most riders plumped for the twin-ribbed drums front and rear.
There were Vincent’s own Girdraulic front forks. Vincent and Irving decided the conventional Brampton girder forks used on the Series A and B Rapides and the Series B Black Shadow were not up to the job, but felt the new telescopic forks that were appearing weren’t suitable either.
Their Girdraulic forks featured Vincent’s own shock absorber in front of the steering head where the spring would be on a girder fork, and telescopic dampers and alloy blades on the forks.
The result: the Black Shadow came with what would today be called mechanical anti-dive. It also meant that the wheelbase was constant. Trail was adjustable thanks to the use of an eccentric bush.
While the mechanically complex front end was heavy, it was impressively strong, with many reports of cars involved in collisions suffering severe damage while the Vincent’s forks came away unscathed.
The spokes were laced to the wheel hubs rather than the brake drums to reduce flexing.
There were two stands (one on each wheel). The brake and gear levers had holes drilled in them so the rider could adjust them to their optimum position,
and the cables had double-wound outer casings.
Stylistically, the Black Shadow had a rakish air, suitable for the devil-maycare rider, in lustrous black, with the sole adornment being the tank transfer and a gold pinstripe or two. Series B models were badged as The Vincent HRD, but from 1950 Series C Models were simply The Vincent.
There was a massive five-inch Smiths chronometric speedometer, so large that it also doubled as a fly screen. It stopped at 150mph, which was unheard of. Not only could it outperform any motorcycle in the world it was faster than the quickest production car of the day, Jaguar’s XK120. Even when Jaguar topped 200bhp in their XK140, the Black Shadow was still faster.
Despite the performance, Vincent didn’t claim the Black Shadow was an out-and-out sportster. “The Black Shadow is a tractable Sports machine, not a super sports or racing machine,” they said. And just to prove it, they then added 15bhp to it, stripped it to the bone, and produced the 150mph-topping Black Lightning racer, of which a few dozen were built and remains one of the few motorcycles to have a song written about it.
Just 11,000 Vincents were built between 1945 and 1955, when production ceased. Of these, 1774 were Black Shadows. A further 15 White Shadows, with polished casings, were also made.
The last few Series D Black Shadows were versions of the fully enclosed Black Prince twins, with the bodywork stripped away. They don’t quite have the presence of the Series C models, and feature a tubular frame spine and a separate oil tank. There was coil ignition and the seat was stuck up in the air with glassfibre panels underneath, rather ruining the lines to some.
The legend of the Black Shadow spread worldwide, with much enthusiasm in the US, where its forte was embarrassing
Harley Davidsons in street drag races by matching the Harley until it reached its limit, and then was changed into top and streaked away into the far distance.
All this power came with a few disadvantages. Lolling about in traffic at low speeds oiled the plugs and upset the clutch. Handling was becoming matched by rivals by 1955, and a determined parallel twin rider could catch a Vincent in the nadgery, the rider admittedly having to watch impotently as the Vincent hurtled off once things started to straighten out.
As journalist and iconoclast Dr Hunter S. Thompson said: “The f ***** ’s not much for turning but it’s pure hell on the straightaway.”
The Black Shadow has more than a touch of class; it comes with an air of breeding and aristocracy. If it were human, it would have a moustache it could twirl, while stealing your girlfriend.