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MOTOR BIKES.
BSA. Type designation.
A= Large twin cylinder (A7=500cc; A10=650cc)
B= Large single (B31 /32 = 350cc; B33/34 =500)
C= 250cc (C11 = 250 rigid, C11g, plunger, C15 = unit construction)
D= 2 stroke. ( 125 - 175cc. The famous Bantam).
Vincent experimented with water-borne motorbikes in the 1950's, the forerunner of today's jet-ski's. They were a
contributory factor in the company's demise.
In 1956 Johnny Allen achieved 214 mph on Bonneville Salt Flats, on a Triumph-engined special.
The first TT race was won at an average of 36 mph.
The 1908 Zenith had a variable speed drive using belts and coned pulleys, exactly as used in DAF cars, and SIG lathes in later years.
The Douglas Dragonfly (a 350cc flat-twin which foreshadowed many of the BMW features) was grossly underpowered. However, it had sufficient torque that if full throttle was applied in low gear whilst on a poor surface (wet grass, for example) the torque could throw the rider off the bike.
(This is from experience!)
George Brown used two Black Shadows, Nero and Super Nero (the latter supercharged), and a much modified Ariel Golden Arrow to win many sprint racing trophies. On Super Nero he achieved…..
<Frustratingly, in my original notes, here were the exact speeds, but these are now illegible.>
The Vincent Black Shadow was reckoned by many people
(including me) to be THE supreme motorbike.
The road holding and braking left something to be desired, and one "modification" was to use the engine in a Norton Featherbed frame, with the Manx full-width hubs, which made a superb machine.
One gearbox that was used was that from a Norton 16H, which managed to withstand powers far above that of its original "home".
Such a rebuild would be counted as sacrilege today, and the prices of all the constituents would make it an expensive
exercise.
At one time, the modification and racing of BSA Bantams was a popular sport.
The limit to tuning was mainly the big-end bearings, but even with this constraint, they could manage straight-line speeds that were rather risky with the poor brakes and flexible frame that was designed for far less power. Cornering at those speeds was another matter!
The Triumph Tiger Cub could be bored out to about 235 cc at which size some people entered it in 250 cc class races. Competing machines usually managed to better it without much trouble.
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