to transporting cargo or injured soldiers.
Although they were not used in combat roles
much due to the prevalence of Jeeps and
armoured vehicles, motorcycles were used for
escorting convoys and scouting missions. Here
are some the main types used by the British
during the war.
BSA WD M20
Small Heath’s 496cc side-valve single was
the guv’nor among two-wheelers supplied
by British manufacturers to our own and
Allied forces. In World War Two, 126,334 BSA
motorcycles were produced from an overall
British total of 425,000, the vast majority M20s,
with a few thousand 250s for training purposes.
With production rising to a peak rate of 1,000
a week, economies of scale meant that in late
1941 an M20 set the War Department back
just £49 12s 2d – cheap enough to replace
if machines were destroyed or had to be
abandoned. But one ex-dispatch rider (DR) did
observe that: “The best M20s were the oldest
ones – the quality seemed to get worse as the
war went on”.
The Small Heath giant, however, did back
up production with service, with factory
personnel giving demonstrations and lectures
all over the UK on maintenance, particularly
in desert conditions, to 250,000 officers and
men. The M20 had not been an obvious war
hero, for dual-purpose use being overweight
(369lbs dry), low on power (13bhp @4,200
rpm), and lacking ground clearance (at 4.6in),
which limited off-road work. But WD doctrine
had changed in 1937, from then on valuing
squaddie-proof simplicity and reliability, to suit
what would shortly be a conscript army.
Troops may have claimed that ‘BSA’ stood
for ‘big, slow and awkward’, but grudgingly
recognised that the M20 was the most durable
of WD bikes; as one wag put it, the
side-valve “didn’t have the power to
wear itself out”. With its bomb-
proof bottom end and stronger
exhaust valve to withstand forces’
low octane MT80 fuel, and a 4.921
compression ratio helping easy
starting, its faults were the kind that
could mostly be fixed in the field.
The single-spring clutch re-
adopted by the WD M20 may
have been simple, but it could
stick, drag, and slip. The
shock absorber nut could
slacken off, the three studs
of the quickly detachable
rear wheel could loosen
off over time and hard
use, causing the stud
holes to elongate. Old sweat DRs
learned to wire the nuts together
before that happened, that is until
BSA changed the rear wheel design,
using dogs instead of studs. Harsh
desert conditions initially provoked
collapsing front springs on the girder
forks, but again the factory soon cleared
this up with different manufacturing
processes for the springs.
The desert and tropical conditions, after some
interim filter arrangements, from late 1943 led
to the fitting of the tank-top universal Vokes
air filter, with a cutaway in the right rear of all
M20s three-gallon petrol tanks, to take the
rubber and canvas hose to the carburettor. One
desert artillery DR recalled that “the soft power
of the side-valve was about right” for the loose
dust of most North African tracks, but they
were fast enough (when new they did just over
60mph) for convoy work on the few hard roads.
Side-valves run hot, so the scorching
sands did the M20 no favours;
but on a crisp, clear day, as
another former DR wrote:“The
Norton
(16H) should have been
the better bike but in
most respects, it was a pig
compared with a good M20.”Matchless WD G3/L
The Matchless G3/L ohv 348cc single
has been described as ‘the Spitfire of WD
motorcycles’ and ‘the superbike of the war’. It
was certainly the one
every British DR
and officer‘The single-spring
clutch re-adopted
by the WD M20 may
have been simple,
but it could stick,
drag, and slip’
The Norton fell in line with the ‘simple
and reliable’ doctrineIn World War Two, 126,334 BSA motorcycles were produced and although the troops
may have said ‘BSA’ stood for ‘big, slow and awkward’ they grudgingly recognised
that the M20 was the most durable of WD bikes