Specific: This machine was received just after
WW II, presumably from the British forces in Germany.
Historical: First attempt to have the M20
accepted by the War Office in the run-up to WW II was in
1935. The War Office requested seven motorcycle
manufactures to submit single-cylinder 500 cm3 machines
for evaluation. BSA Motorcycles Limited offered the 499
cm3 side-valve type W35-6. The bike failed to complete
the obligatory Mechanisation Experimental Establishment
(MEE) 10.000 miles reliability test, and in 1936 a 496
cm3 version, the first M20 was submitted. This version
failed the trials as well,but did at least complete them,
and during 1937 further 3 versions were submitted.
The improved models was judged as "acceptable"
and 2 batches with small changes were delivered in 1937.
Volume production of what was first known as the K-M20
took place from 1939 (designation changed to W-M20 within
the same year), and after final refining it was
standardised in 1942. From that on only minor changes
were made to the bike.
The M20 was intended as a general purpose motorcycle for
task such as convoy escort and long distance
The motorcycle was used by all British armed services,
and remained the standard service machine through the
1950´s. Several was still in use at the end of the
Around 126.000 were made - more than any other WW II
Length: 2.18 m (86 inches).
Width: 0.73 m (29 inches).
Height: 0.99 m (39 inches).
Weight: 176 kg (392 lb.).
Engine: Own 1-cylinder, 0.496 cm3 (30 cubic inches)
displacement, air cooled, carburettor.
Horsepower: 12 at 4.100 rpm.
Transfer case: None.
Electrical system: 6 volt.
Tyres: 3.25 - 19.
Fuel type: Petrol.
Fuel capacity: 16 liter (3.5 gallon).
Range: 280 km (175 miles).
Crew: 1 + 1.
Additional: Some of the RAF bikes were
added a sidecar manufactured by Swallow.