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BSA M 20 500
When World War 2 began,
BSA was Britain's major motorcycle factory, with the proud boast
that 'one in four is a BSA'. The firm had supplied the armed forces
in World War I, and as befitted a company that began as an armament
manufacturer, had geared up to produce munitions as early as 1935.
They would go on to become the biggest supplier of motorcycles to
the forces, in the unlikely form of their model M20.
Originally launched in 1937, mainly
as a sidecar model, the M20 used a 500cc side-valve engine in a heavy frame. BSA
had been supplying the War Office with a variety of models for evaluation, and
in some cases purchase, since the late 1920s. The company originally submitted
the M20 in 1936, only to see it fail, owing to heavy engine wear. Resubmitted
the next year, it passed, and a small batch was purchased in 1938.
The War Office then issued an
official policy that favoured the machines already in service, whose reliability
was well known, principally the Norton I6H and M20. Large quantities of the BSA
model were bought. Heavy, bulky, slow and with limited ground clearance, the M20
had far from an ideal specification, but it was rugged, generally reliable and
was easily repaired. Special fittings included a long, spiked prop-stand for
field use and a large headlamp, fitted with a blackout mask. In 1942, a shortage
of rubber led to rubber hand grips being replaced with canvas fittings and
footrests with simple metal ribs. A large air filter mounted on the tank and
coupled to the carburettor by a hose was fitted for use in climates such as the
African desert. As a result part of the rear of the tank had to be cut away.
Comprising details from various
years between 1940-42, this BSA M20 is typical of WD models that were rebuilt
many times, losing their original identity in the process.
The M20 used BSA's heavyweight girder forks,
Purchased for despatch and escort
duty, the M20 served in many theatres of war. Over 125,000 were purchased by the
armed forces. The finish consisted largely of applying khaki paint liberally,
including the engine, tyres and even the saddle, with different camouflage
schemes in various countries.
Vast numbers of M20s were discharged
at the end of hostilities, and after gaining a new coat of paint they were
snapped up by a transport-hungry
public. However the model stayed in service in smaller numbers for many years in
some cases as late as 1971. The vast quantities built mean that ex-WD M20s are
still in use in many parts of the world, and it is even possible to find that
new spares are still available. The civilian model was manufactured until 1955,
with its 600cc cousin the M2I soldiering on until 1963, the last side-valve
built in Britain.
Engine
Air cooled, four stroke, single cylinder,
side valves, capacity 469cc bore and stroke 82 x 94 mm, 13 hp @ 4200 rpm |
