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military Nortons, a number of 6V
negative (-) earth
systems have been used based on the existing equipment or the
operational requirements of the time at which they were applied. It was a
relative simple system and used
by most of the contemporary British motorcycle manufacturers. Some used
invented darkness" or Lucas "Prince of darkness" are some of
the many adjectives for the products of Lucas manufacture. Many of the
problems were caused by bad maintenance or by the harsh environment into
which the bikes were operated.
Electrical equipment variation two:
The wiring diagram changed over the years either to cater for the change from the
sused until 1941 was the basic civilian scheme having the 3 position headlamp switch (U 39). "OFF", "L" (pilot bulb and rear light) and "H" (main bulb and rear light) and an additional High/Low beam "Dip/Dipper/Dimmer" switch mounted on the left hand side of the handlebar. Civilian bikes had a brake light option. All military paperwork shows systems without the brake light so it is assumed that that they were never used on military bikes.
T position switch introduced between Oct 21st (latest known original MC) and somewhere in December.
On May 5th 1941, DME Circular B.141 mandated the removal of the Dipper
switch from the existing motorcycles and the fitting of new headlamp masks
Nearing the end of the war, an "improved" wiring scheme was
introduced, to reduce the number of wires running from the front fork to
the rest of the machine after it was recognised that many electrical
faults developed through chafing, resulting from the continues movement of
the front fork. This system was also introduced on other brand motorcycles
like the BSA M20.
Colour codes for the simplified scheme are unknown but expected to be in line with the earlier where similar.
1937 to 1941
1941 to 1944/45?
Remains of original wires found on a switch as applied in the late
war electrical system (1944/45) appeared to be rubber like, similar as
Picture from article of Steve Madden, courtesy Henk Joore's WDBSA.nl website.
At least 2 different diameter wires have been found, approximately Ø 4,6 mm and Ø 5,7 mm as measured on the insulation.
Wiring remains on a late-war (re?)built machine showed to have cloth covered leads. It was not possible to assure this was factory applied. Whether the use of the cloth encapsulated wire was widespread is difficult to say. Cloth encapsulated wiring was used on motorcars and motorcycles in the 20ties and 30ties.
Batteries and CVC
Because of the different charging requirements there were also two types of MCR1 CVC's. Each clearly marked with either "Ni-Fe" or "Lead Acid" above the FADE markings. The "Lead Acid" marking was finally deleted around 1941 when the Ni-Fe's were all replaced by Lead Acid batteries and the distinction was not necessary anymore. Lead Acid batteries could work with Ni-Fe CVC's but it was only allowed for a short period and not recommended.
(but not all) Lucas parts are provided with the manufacturing date stamped into them. If
you really want to restore a bike to "factory" fresh condition,
searching for correctly dated Lucas equipment should make your life
The Electrical equipment picture page gives some indication on what the different parts basically look like.