United Kingdom - British
Birmingham Small Arms - BSA Motorcycle WD M20
Serial Number: 103026
Registration Number: C5213726
History of Birmingham Small Arms - BSA Motorcycle WD M20 Serial Number: 103026
This War Department M20 is the 6209th of 8000 motorcycles produced for contract S2603 (December 1943 - July 1944). It was
produced and was delivered to the War Office, London in roughly May of 1944. Many of the BSA records were destroyed by
enemy action during WWII in England, so the exact date of production and delivery is not known. The year listed is based on
known BSA annual production contract numbers. The Registration Number: C5213726, was painted in white paint on both
sides of the front of the fuel tank, 9 inches long with letters 1.5 inches tall by 1 inch wide.
This BSA M20 complete frame, motor mounts, chain guard and rear wheel were obtained by QuestMasters in 2018. This M20
was found in Vermont, United States. The tire shown on the rear wheel is an original War Department produced tire. The
original wartime paint is still present. The wartime service of the M20 is currently unknown.
The Serial Number for all Birmingham Small Arms - BSA M20 Motorcycles is stamped on the left lower side of the frame just
behind the front fork tube. This 1944 BSA is marked WM20 103026.
This original wartime photo shows a 1944 BSA M20 Registration Number C5213661, marked with the stylised winged helmet
insignia, on the fuel tank, for the 1st Polish Armored Division - part of the 1st Canadian Army. This M20 was produced 65
motorcycles before the 1944 BSA M20 Serial Number 103026 Registration Number C5213726, in the QuestMasters Museum
collection.
Note the placement of the BSA logo and registration number on the fuel tank in this photo.
British Military Keycard No. 2, above photo. After WWII, the 1944 BSA M20 Serial Number 103026 Registration Number
C5213726 continued to serve in the British Military in Germany at 17 RVD BAOR (17th Rear Vehicle Depot, British Army Of the
Rhine). It received a new registration number of  93YC04, which replaced the original wartime C number. This motorcycle saw
military service through at least February 21st 1969, as seen on the last line of the above document.
This original wartime photo shows a British Sergeant riding a 1944 BSA M20 Registration Number C5213784, which is 58
motorcycles later than 1944 BSA M20 Serial Number 103026 Registration Number C5213726, in the QuestMasters Museum
collection.
Note the placement of the BSA logo and registration number on the fuel tank in this photo.
POST WWII SERVICE:
For more WWII BSA Motorcycle history, please visit The BSA W.D. M20 Website:
http://www.wdbsa.nl/index.htm
M20 103026 C5213726
BSA M20 Forks, or Girders, above two photos.
These forks were recently obtained in the United Kingdom for the restoration of M20 103026. The original wartime olive drab
paint is present under the post-WWII black paint. These forks are from M20 Serial Number 20563.
BSA M20 7805 Engine, above two photos.
This engine is from BSA M20 Deluxe Serial Number 7805, delivered to the War Office on October 26th 1939.
This engine was found in Michigan, United States and was painted in post-WWII olive green during rebuilding in 1952.
Although the engine is 4 years earlier than M20 103026, it will be used during the restoration.
BSA M20 7805 Engine rebuild plate, above photo.
This engine is from BSA M20 Deluxe Serial Number 7805, delivered to the War Office on October 26th 1939.
This engine was rebuilt on September 9th 1952 by 12 HEAVY WORKSHOP R.E.M.E. (Royal Electrical and Mechanical
Engineers), located at the previous Hanomag Truck Factory, Hannover Germany.
The rebuild added .020 to the main bearing.
BSA M20 7805 delivery document, above photo.
This document shows BSA M20 Deluxe Serial Number 7805, being delivered to the War Office on October 26th 1939 with
registration number C3934738.
The Tally Number 15635 currently has an unknown meaning.
The engine from 1939 BSA M20 7805 will be used in the restoration of 1944 M20 103026.
History of BSA M20 7805 C3934738:
BSA M20 7722 Registration Number C3931142, above photo.
The M20 Deluxe motorcycle shown is 83 motorcycles prior to BSA M20 Deluxe Serial Number 7805, which the above engine is
from.
This original wartime photo from the Imperial War Museum, shows a 1944 BSA M20 Registration Number C5213537, marked
with the stylised winged helmet insignia, on the fuel tank, for the 1st Polish Armored Division - part of the 1st Canadian Army.
This M20 was produced 189 motorcycles before the 1944 BSA M20 Serial Number 103026 Registration Number C5213726, in
the QuestMasters Museum collection. In this photo, Captain F. Perepeczko (left), 1st Polish Armoured Division, Normandy,
France 1944. The Serial Number of the Ford GPW or Willys MB Jeep is 33564.
Note the placement of the BSA logo, registration number and the Allied Star on the fuel tank in this photo.
BSA M20 Fuel Tank, above photo.
This M20 fuel tank was removed from M20 Serial Number 117108 and is shown sand blasted and primer painted.  
This style of fuel tank has a "cut-off" section on the right rear of the tank. This was introduced to accommodate the "Vokes"
style air filter that was mounted on top of the fuel tank. The "cut off' tank is part no. 66-8211 and was introduced in 1943 for
M20 contract numbers S2603, S5209 and S7218, the end of WWII production.
BSA M20 Oil Tank, above two photos.
This M20 Oil Tank, Part Number 65-8442, was removed from M20 Serial Number 117108 and is shown crushed glass blasted
to bare metal and red oxide primer painted. The Oil Tank also includes Filler Cap, Part Number 66-8351 and is mounted with
(3x) 15-480 Bolt (5/16"-26x1 1/8"), (3x) 24-8784 Washer and (3x) 66-8347 Distance Washer.
The Oil Tank is attached to the right side of the motorcycle with 66-4889 Oil Tank Support Plate that is shared with the
Battery Carrier. The Support Plate is mounted to left side of the frame with (2x) 15-1120 Stud (5/16"-26x1 1/2") and (2x) EA80
Nut. Page 92, 93 and 94, BSA Catalogue of Replacement Parts for all 1940 Models and page 17, Spare Parts List for BSA
500cc S.V. Model WD/M20 Contract S 2603.
BSA M20 Tool Box, above two photos.
This M20 Tool Box was removed from M20 Serial Number 117108 and has been restored with closing handle and brackets.
This M20 Tool Box is Part Number is 65-9038 with 65-9028 Screw Fastener, 65-9021 Tool Box Strap with (2x) 15-7161 Bolt
(1/4"-26x1/2"), (2x) EB113 Nut (1/4"-26) and (2x) 29-541 Shakeproof Washer (1/2" External Diameter, External Tooth), 27-9001
Clip with A176 Distance Washer, 24-225 Bolt, 29-541 Shakeproof Washer (1/2" External Diameter, External Tooth), K234A
Washer, M263 Nut, and 15-7171 Mudguard Bolt (1/4"-26x1/2"), K197 Spring Washer (1/4") and EB113 Nut (1/4"-26) page 108
and 109, BSA Catalogue of Replacement Parts for all 1940 Models and page 20, Spare Parts List for BSA 500cc S.V. Model
WD/M20 Contract S 2603.
BSA M20 Handle Bars, above photo.
This M20 handle bars were removed from M20 Serial Number 117108 and is shown unrestored in post-WWII chrome plating.
BSA M20 Skid Plate, above photo.
This M20 skid plate was removed from M20 Serial Number 117108 and is shown sand blasted and primer painted.
BSA M20 Muffler or Silencer, above photo.
This M20 muffler is a post-WWII reproduction. The chrome plating will be removed prior to use and the mounting tab, shown
on the left, will be relocated to the center of the muffler.
BSA M20 Gear Box or Transmission, above two photos.
This M20 gear box was removed from M20 Serial Number 93874 and will be used in the restoration of the QuestMasters
Museum 1944 BSA Serial Number 103026.
BSA M20 Rear Mudguard or Fender, above photo.
This M20 Mudguard was removed from a 1941 BSA M20 Serial Number *1796 and will be used in the restoration of the
QuestMasters Museum 1944 BSA Serial Number 103026. The luggage carrier that holds the Pannier bag racks is a replica and
produced in India.
BSA M20 Lucas Battery Carrier, above three photos.
This M20 Lucas Battery Carrier was removed from a 1941 BSA M20 Serial Number *1796 and will be used in the restoration of
the QuestMasters Museum 1944 BSA Serial Number 103026. The carrier is marked on the front: JOSEPH LUCAS LTD.
BIRMINGHAM ENGLAND MADE IN ENGLAND. The rear of the carrier retains the original 1941 green paint with red oxide
primer showing through. This original painted surface will not be restored and installed on the motorcycle intact.
BSA M20 Lucas DU42 Headlight, above three photos.
This original 6" M20 Lucas DU42 Headlight will be used in the restoration of the QuestMasters Museum 1944 BSA Serial
Number 103026. It was fitted to BSA M20 motorcycles from 1942 through 1945. The headlight is marked on the bottom of the
headlight body: DU42. The four position bakelite switch was also produced by Lucas. The Lucas Ammeter shown here was
produced in 1937. Although it is the same size as the wartime CZ27 Ammeter that was fitted on the M20, this 1937 example
shows a high level of 20 amps. The CZ27 was only rated to a maximum of 8 amps on the face of the indicator. The Headlight
Mask or Blackout Light Shield is a modern accurate replica produced in India.
This
Lucas Headlight Group is Part Number 515532 page 74, BSA Catalogue of Replacement Parts for all 1940 Models and
Headlamp Assembly Part Number DU42
page 23, Spare Parts List for BSA 500cc S.V. Model WD/M20 Contract S 2603.
BSA M20 Rear Tire or Tyre, above three photos.
During inspection for the restoration of the 1944 BSA Serial Number 103026, in the QuestMasters Museum collection, it was
realized that the rear tire or tyre is original British War Department issue. The tire was manufactured by MICHELIN, size 3.25 -
19, Golden Arrow and has the War Department Broad Arrow marking with casting number 5463-3. It will be removed and
preserved during the restoration.
BSA M20 Frame and Rear Wheel, above three photos.
The 1944 BSA M20 Serial Number 103026 has been crushed glass blasted to bare metal and red oxide primer painted.
Test fitting the gear box, engine, fuel tanks and front girder forks on the 1944 BSA M20 Serial Number 103026.
The BSA M20 Tool Box Strap is becoming increasing difficult to find. QuestMasters fabricated this bracket from drawings
provided on the BSA M20 site:
http://www.wdbsa.nl/download/tool_box_bracket.pdf
This M20 Tool Box Strap is Part Number is 65-9021 and is attached with (2x) 15-7161 Bolt (1/4"-26x1/2"), (2x) EB113 Nut
(1/4"-26) and (2x) 29-541 Shakeproof Washer (1/2" External Diameter, External Tooth), page 108 and 109, BSA Catalogue of
Replacement Parts for all 1940 Models and page 20, Spare Parts List for BSA 500cc S.V. Model WD/M20 Contract S 2603.
The BSA M20 Kickstart Crank, mounted to the right side of the gear box. This was obtained from a 1942 BSA M20 and retains
some of the original green wartime paint.
This M20 Kickstart Crank is Part Number is 15-4197 with Cotter Pin EB56, Cotter Pin Nut EB57 and Cotter Pin Washer EB58,
page 36 and 37, BSA Catalogue of Replacement Parts for all 1940 Models and page 8, Spare Parts List for BSA 500cc S.V.
Model WD/M20 Contract S 2603.
BSA M20 Rear Chaincase or Inner Primary Case, above two photos.
This M20 Rear Chaincase, with fixed fittings and sliding plate, is factory stamped on the inside with Part Number 66-7602,
which is the part number for the Chaincase assembly. The actual Part Number is 66-7601, page 88 and 89, BSA Catalogue of
Replacement Parts for all 1940 Models and page 16, Spare Parts List for BSA 500cc S.V. Model WD/M20 Contract S 2603.
BSA M20 Gearbox Clutch, above photo.
Shown here are two Gearbox Clutch Assemblies, the top one is a disassembled original and the bottom one is a mixture of
assembled original and replacement parts. The Clutch Assembly is Part Number 66-3808 which consists of: 66-3809 Clutch
Chainwheel, (22x) 26-650 Chainwheel Roller, 66-3811 Clutch Sleeve, 66-3813 Cork Ring, 15-4306 Centre, (8x) 15-2419 Ferodo
Ring or Friction Plate, (4x) 66-3812 Driving Plate, (3x) 15-4307 Driven Plate, 15-4308 Sliding Plate with bolts, (6x) KB113 Nut,
(6x) K197 Spring Washer, 15-4311 Spring, 15-4312 Retaining Nut, 15-4313 Operating Cap, 25-4861 Operating Cap Bush,
Operating Cap Bush Ball 5/16" Diameter, EA60 Operating Cap Bush Locknut, 26-4138 Operating Cap Bush Locking Washer,
15-4315 Clutch Cover, 15-4316 Cover Joint Washer or Gasket, (8x) EB379 Cover Screw and (8x) 24-7068.
Listed on Page 42 and 43, BSA Catalogue of Replacement Parts for all 1940 Models and page 8, Spare Parts List for BSA
500cc S.V. Model WD/M20 Contract S 2603.
Not listed on this page of the original manual, but located inside of the Gearbox Clutch is Part Number 15-374 Mainshaft Nut.
The part shown here, 15-5315 Operating Cap has been modified with a brazed nut, which is incorrect. This will be corrected
during restoration.
Listed on page 9, Spare Parts List for BSA 500cc S.V. Model WD/M20 Contract S 2603, and part of the Gearbox Clutch:
65-3160 Operating Lever, 65-3162 Operating Lever Fulcrum Pin, 25-4251 Operating Lever Thrust Pin, 27-4411 Operating Lever
Thrust Pin Nut, 15-4261 Clutch Push Rod and 15-270 Push Rod Cork Gland Washer.
BSA M20 Oil Tank Support Plate, above photo.
This M20 Oil Tank Support Plate, Part Number 66-4889, was fabricated by QuestMasters using the drawings provided on the
BSA M20 site:
http://www.wdbsa.nl/Oil_tank_bracket.htm
The welds were intentionally made random to replicate factory mass production. This Plate is shown from the Oil Tank side
(right side of the motorcycle).
AMAL Carburetor Model 276AW/1BB, above two photos.
The original AMAL carburetors were based on the products of three companies that made up AMALgamated Carburetters Ltd.
In 1939, the Model 274, 275, 276 and 289 were introduced, which had two internal primary air passages in the base of the jet
block. Each Type Number indicates a different size of the carburetor casting. These markings are stamped on the top of the
flange that mates to the cylinder head. The suffix after the / symbol indicates the type of jets, float chamber and which
machine it was fitted to with that carburetor. The AMAL Type 6, Model 276 was used from 1939 to 1954.
The 1940-1945 BSA M20 motorcycle, with 496cc engine, used the AMAL Model 276C/1B.
The AMAL Model 276AW/1BB was originally fitted to the 1946-1948 BSA B31 motorcycle with 348cc Engine.
This carburetor will be initially used in the restoration of BSA M20 S/N 103026. The float, show on the left side of the
carburetor in these two photos, will be positioned on the right side, when mounted on the BSA M20.
BSA M20 Universal Saddle or Seat, above two photos.
This Universal Saddle is shown with original early BSA M20 green paint
on the underside and has the original Saddle Cover.
This
saddle is listed as H. Terry & Sons Ltd, Redditch Part Number S707, page 78, BSA Catalogue of Replacement Parts for all
1940 Models and
Universal Saddle MT1/TE/S831 page 20, Spare Parts List for BSA 500cc S.V. Model WD/M20 Contract S 2603.
BSA M20 Universal Saddle or Seat, Springs and Bolts, above photo.
Th
e Universal Saddle suspension at the rear of the seat consisted of (2) Main Spring, (2) Rear Support Strap Part Number
66-9197, (4) EA80 Nut (5/16" - 26) and (4) 35-382 Shakeproof Washer (5/16" external tooth).
P
age 78, BSA Catalogue of Replacement Parts for all 1940 Models and page 20, Spare Parts List for BSA 500cc S.V. Model
WD/M20 Contract S 2603.
Lucas Magdyno M01*2 463957 L6 79, above three photos.
Lucas produced Magdyno's for Ariel, BSA, Norton, Royal Enfield and Triumph
- before, during and after World War Two. The
Magdyno shown here
is a Lucas Model M01*2 463957 L6, produced July 1939 (date code 79, Month 7 - July, Year 9 - 1939).
This Magdyno
currently has an unknown motorcycle model application. It was removed from a wartime BSA M20 motor and
may be used for the restoration of the BSA M20 Serial Number
103026. This Magdyno has clockwise rotation as shown on the
front plate.
The correct Magdyno for wartime produced BSA M20's are the M01*4 AC20 and later M01*6 AC20, both with counter-
clockwise rotation.

The Magdyno Unit, Part Number 465109 is listed on page 74, BSA Catalogue of Replacement Parts for all 1940 Models and as
Magdyno Type M01/6 AC20
page 21, Spare Parts List for BSA 500cc S.V. Model WD/M20 Contract S 2603.
BSA M20 Speedometer Bracket, New-Old-Stock, Original Paint, above photo.
The
Speedometer Bracket Part Number 15-8958 is listed on page 110, BSA Catalogue of Replacement Parts for all 1940
Models and
listed as Speedometer Bracket Part Number 66-9114 page 13, Spare Parts List for BSA 500cc S.V. Model WD/M20
Contract S 2603.
BSA M20 Lucas DU42 Headlight Brackets, above photo.
Th
e M20 Lucas DU42 Headlight four small brackets, shown here have been crushed glass blasted and primer painted.
Th
e Headlight Bracket, Top, Part Number 15-9001 and Bottom, Part Number 66-9078 are listed on page 110, BSA Catalogue of
Replacement Parts for all 1940 Models and
Headlight Bracket, Top, Part Number 66-9077 and Bottom, Part Number 66-9076
on
page 11, Spare Parts List for BSA 500cc S.V. Model WD/M20 Contract S 2603.
BSA M20 7805 Engine Cases, above two photos.
The engine has been completely disassembled and "Vapor Blasted"
, a process that uses very fine crushed glass sprayed with
90 PSI water, resulting in factory
-finish cast aluminum, without removing any base material. The timing case is marked 66-
1602 in raised numbers on the inside of the case and hand stamped 66-1600 8855 on the side of the case. The drive case is
marked 66-1604 in raised numbers on the inside of the case and hand stamped 8855 on the side of the case.
The drive case is
also stamped with the motorcycle Serial Number WM20 7805.
Both cases are hand painted 911 in red paint, presumably
during rebuild on September 9th 1952 by 12 HEAVY WORKSHOP R.E.M.E.
, to keep track of the two case halves during
rebuild. These markings were intentionally not removed during "Vapor Blasting" to preserve the history of this engine.
The
timing cover is marked 66-
1919 in raised numbers on the inside of the case

The engine cases were blasted by Urban East Motorcycles and Fabrication, Lorton Virginia U.S.A.:

www.theurbaneastfabshop.com
BSA M20 7805 Engine Piston, above photo.
The engine
piston was also "Vapor Blasted". The piston is marked on the top with the BSA logo, Part Number 66-1024, 6, M,
with an inspection stamp: a circle with V 160. The inside has the raised cast Part Number 66-1024, C56, 178 7-4.
BSA M20 Front Wheel, New-Old-Stock, Original Paint, above two photos.
Th
is front wheel assembly was supplied by the War Department as a complete spare parts assembly Part Number 66-5536
and issued without front brake and tyre (tire). This original New-Old-Stock World War Two production wheel as found in
Greece and had never been fitted to a motorcycle.
The
Front Wheel Assembly, with WM1-20 rim with spindle and bearings, less brake and tyre are Part Number 66-5534 and
listed on page
66, BSA Catalogue of Replacement Parts for all 1940 Models and listed as Part Number 66-5536 page 12, Spare
Parts List for BSA 500cc S.V. Model WD/M20 Contract S 2603.