224:. By early 1942 a new large rear carrier was fitted to hold universal WD steel pannier-frames and bags. This meant repositioning the long prop stand to forward of the nearside rear wheel spindle nut. In 1943 further modifications were made including redesign of the crankcase sump shield and fitting of the Vokes high capacity air cleaner, which was a box shaped canister on top of the fuel tank and was intended to assist operations in dusty environments. In early 1945 a push-button switch was introduced for the headlight and the main lighting switch relocated to a bracket beneath the offside of the saddle.
147:
32:
282:
233:
314:. The intake port fed by the carburetor, originally horizontal, was re-drilled at a steep angle into the cylinder casting so it pointed up at the underside of the intake valve. The motorcycle did however retain the long BSA prop stand that hinged under the seat and clipped to the rear mudguard when not in use — so it looked like a stock M20. In October 1995 an M20 fitted with a
255:, while a third machine was used in service trials. In 1938 when a small batch was commissioned. Criticised for being heavy and slow, with poor ground clearance it was saved by its reliability and ease of maintenance. As the need for transport quickly gained pace orders were placed for larger quantities. Most BSA M20 motorcycles were used by the
203:
dry putting out the fire. As well as 53 workers killed, 89 were injured and it was six weeks before the last of the bodies could be recovered. Much of the factory and equipment was destroyed or damaged but BSA had 67 factories so work was transferred elsewhere and production of the BSA M20 continued.
166:
Early K-M20 models from 1939 were made from standard civilian parts with the addition of military fittings, such as a large 8-inch Lucas DUl42 headlight (fitted with a black out mask), a timing-gear cover with a screw-in plug for access to the magneto drive-pinion nut and special filler caps for the
246:
The M20 failed on its first submission to the War Office in 1936 due to 'unacceptable engine wear'. The prototype machine required a replacement piston and cylinder after approximately 6,000 miles. In 1937 three more M20s were submitted to the War Office for testing. Two of these machines only just
293:
placed a large order and their yellow and black M20 combinations became a familiar sight on
British roads. The 1945 wartime cast iron engine continued in production until 1951, when an alloy cylinder head was introduced but otherwise it remained largely unchanged. Spares began to become harder to
212:
From
October 1939 the K-M20 was designated the W-M20 and modified to include girder-forks and removal of the valanced rear mudguard. During late 1940 some civil specification M20s were purchased by the War Office which were civil models with a military paint scheme. In 1941 front and rear number
238:
235:
234:
237:
267:
also commissioned M20's from BSA. Designed as a general-purpose motorcycle for convoy escort and dispatch use, the M20 saw action in almost every theatre of war. After the war the BSA M20 model continued in military service throughout the
167:
petrol and oil tanks. These early military M20 models were also fitted with a long spiked prop stand on the rear nearside pivoted from a lug brazed on to the rear frame tube. Factory ledgers show that BSA exported K-M20 models to
162:
the BSA M20 started development in 1937 as a heavy-framed sidecar model with a simple 500 cc single cylinder side valve engine. It had low compression and plenty of low-end torque through a standard BSA gearbox.
272:
of the 1950s and in smaller numbers until the end of the 1960s, partly due to the low cost and easy availability of spare parts but also as a result of six years of harsh conditions with no serious failures.
294:
find in the 1950s, however, and the simple design was overtaken by modern twin cylinder motorcycles, so it was discontinued in 1956, but the 600cc M21 went on until 1963, when it was also discontinued.
302:
As well as being painstakingly restored by enthusiasts to accurate wartime specification, the M20 has also been developed by specialists for speed trials. A 1938 BSA M20 ridden by Bill
Jenkins from
220:
From 1942 there was a shortage of rubber so handlebar grips and foot pegs were replaced by canvas covered metal items and production was standardised, with only minor modifications until the end of
217:(later replaced with pressed steel). The DU142 headlight was replaced with a smaller 6 in Lucas DU42, with a hooded, slotted black-out shield, and a universal L-WD-MCT1A tail light was fitted.
236:
199:
and at 9.25pm a low flying aircraft dropped two bombs which destroyed the southern end of the BSA building in
Armoury Road. Rescuers included BSA's own fire brigade who pumped the
289:
The BSA M20 was a reliable and affordable form of post war transport, so BSA repainted the khaki WD models black and they became particularly popular as a sidecar motorcycle.
134:
in 1936, the M20 evolved into one of the longest serving motorcycles in the history of
British military motorcycling, as well as becoming the most numerous type produced for
213:
plates were removed and between 1941 and 1942 active service use in North Africa showed the need for easy adjustment of the fork dampers. Special damper knobs were made of
1518:
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318:
crankshaft sprocket and running on a 95% methanol / 5% acetone mix ridden by Pat Jeal achieved a terminal speed of 112 mph at the disused airfield of
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BSA were
Britain's largest motorcycle manufacturer with a long history of armaments supply to the armed forces. Designed by
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1276:
608:
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404:
455:
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making it the fastest M20 in the world. The original side-valve engine was extensively modified and fuelled with
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42:
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943:
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BSA workers employed making the M20 were killed in an air raid on the BSA factory in
Armoury Road,
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on the night of
Tuesday 19 November 1940. The factory was one of the main targets for the
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with 126,000 in active service. Many are still in use around the world today.
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82 mm × 94 mm (3.2 in × 3.7 in)
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130:. Although initially viewed as a near failure by the
504:
1626:
365:The Complete Encyclopedia of Classic Motorcycles
179:, as well as civilian dealers and distributors.
249:Military Vehicles and Engineering Establishment
1354:British Commonwealth utility vehicles of the
1339:
658:
479:The Illustrated guide to military motorcycles
390:
388:
386:
384:
363:De Cet, Mirco (2005). Quentin Daniel (ed.).
247:passed the 10,000 mile suitability tests at
1650:World War II vehicles of the United Kingdom
481:. Anness Publishing Ltd. pp. 184–185.
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1332:
665:
651:
507:British Forces Motorcycles 1925 – 45
394:
381:
529:
62:496cc single cylinder side valve 4 stroke
523:
500:
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306:achieved a top speed of 108 mph at
280:
231:
145:
420:
418:
416:
358:
356:
1627:
362:
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1327:
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458:from the original on 29 December 2008
285:A former AA BSA patrol bike from 1951
611:from the original on 27 January 2009
505:Orchard, C. J.; Madden S.J. (1997).
476:
413:
353:
276:
1645:Motorcycles introduced in the 1930s
672:
227:
13:
297:
14:
1666:
626:
602:
580:
342:List of motorcycles of the 1950s
337:List of motorcycles of the 1940s
332:List of motorcycles of the 1930s
207:
30:
1576:Car, Heavy Utility 4×2 Ford C11
596:
605:"BSA M20 & M21 Motor Mods"
574:
548:
532:The British Classic Bike Guide
470:
444:
141:
1:
1303:Birmingham Small Arms Company
395:Kemp, Andrew; De Cet (2004).
347:
120:Birmingham Small Arms Company
43:Birmingham Small Arms Company
1581:Car, Light Utility ("Tilly")
201:Birmingham and Warwick canal
7:
1655:Single-cylinder motorcycles
426:"BSA Model M20 496cc Facts"
325:
10:
1671:
1425:Diamond T tank transporter
583:"BSA M20 Bonneville Racer"
556:"Model recognition points"
291:The Automobile Association
122:(BSA) at their factory in
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530:Westworth, Frank (1998).
100:
90:
80:
66:
56:
48:
38:
29:
509:. Suton Publishing Ltd.
1313:Norton Villiers Triumph
1308:List of BSA motorcycles
399:. Mirco. Bookmart Ltd.
1051:BSA C15 Sportsman SS80
752:A65 Firebird Scrambler
738:A10 Spitfire Scrambler
367:. Rebo International.
286:
243:
151:
1031:B25T Victor Trail 250
766:A65 Lightning Clubman
534:. Haynes Publishing.
397:Classic British Bikes
308:Bonneville Salt Flats
284:
242:Starting a 1942 W-M20
241:
149:
1640:Military motorcycles
771:A65 Lightning Rocket
733:A10 Rocket Gold Star
1609:Royal Enfield WD/RE
1604:Harley-Davidson WLA
1026:B25SS Gold Star 250
939:B44 Victor Roadster
781:A65 Spitfire Hornet
638:Video of BSA WD M20
633:BSA wartime gallery
183:M20 factory bombing
154:At the outbreak of
26:
1555:Thornycroft Tartar
1550:Thornycroft Nubian
1493:1, 2, 3, 6 & 8
1444:Trucks and lorries
1364:Artillery tractors
970:B40 Sportsman SS90
944:B44 Victor Special
888:Gold Star Catalina
832:A7SS Shooting Star
562:on 1 December 2008
477:Ware, Pat (2010).
432:on 16 October 2008
287:
244:
152:
24:
21:Type of motorcycle
16:British motorcycle
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1621:
1571:Car, 4-Seater 4×2
1524:Leyland Retriever
1515:
1417:Tank transporters
1321:
1320:
1245:
1244:
1097:
1096:
929:B44 Victor Enduro
924:B44 Shooting Star
863:B50T Victor Trail
488:978-1-84681-448-8
374:978-90-366-1497-9
277:Civilian versions
239:
118:formerly made by
108:
107:
1662:
1564:Utility and cars
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1435:Scammell Pioneer
1407:Scammell Pioneer
1392:Guy Quad-Ant FAT
1356:Second World War
1348:
1341:
1334:
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1107:
853:B50MX Moto Cross
748:A10 Super Rocket
723:A10 Golden Flash
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558:. Archived from
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428:. Archived from
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270:national service
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228:Military service
86:13bhp @4,200 rpm
34:
27:
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1635:BSA motorcycles
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1298:BSA motorcycles
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1227:B22 Empire Star
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1206:R33-5 Blue Star
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1180:W33-8 Blue Star
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1016:B25FS Fleetstar
1004:
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883:DBD34 Gold Star
858:B50SS Gold Star
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801:T65 Thunderbolt
796:A65 Thunderbolt
743:A10 Super Flash
728:A10 Road Rocket
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674:BSA motorcycles
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298:112 MPH BSA M20
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265:Royal Air Force
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96:4 Speed / chain
52:1937–1955
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697:A70 Lightning
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316:BSA Gold Star
313:
312:nitrous oxide
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208:Modifications
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101:Fuel capacity
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25:BSA M20 / M21
19:
1598:
1519:Leyland Lynx
1510:(Mk I &
1382:Albion FT15N
1377:Albion CX22S
1267:Bert Hopwood
1159:
1056:C15 Starfire
1021:B25 Starfire
892:
776:A65 Spitfire
702:A75 Rocket 3
613:. Retrieved
598:
586:. Retrieved
581:Bath, Bill.
576:
564:. Retrieved
560:the original
550:
531:
525:
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478:
472:
460:. Retrieved
446:
434:. Retrieved
430:the original
396:
364:
301:
288:
257:British Army
245:
222:World War II
219:
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186:
173:South Africa
165:
156:World War II
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136:World War II
111:
109:
92:Transmission
39:Manufacturer
18:
1591:Motorcycles
1491:Fordson WOT
1471:Bedford OXD
1466:Bedford OYD
1451:Austin K2/Y
1397:Morris CDSW
1372:AEC Matador
1293:BSA Company
1104:motorcycles
836:A50 Cyclone
683:motorcycles
603:Jeal, Pat.
189:Small Heath
142:Development
124:Small Heath
1629:Categories
1539:Morris CS8
1502:Karrier K6
1476:Bedford QL
1461:Bedford MW
898:Unit twins
806:Unit twins
786:A65 Rocket
756:A65 Hornet
718:A10 series
615:10 January
588:10 January
566:10 January
462:10 January
436:10 January
348:References
261:Royal Navy
193:Birmingham
150:The engine
132:War Office
128:Birmingham
116:motorcycle
49:Production
1545:Morris C9
1534:Morris PU
1486:Commer Q2
1481:CMP Truck
1456:Austin K5
1430:Mack EXBX
1257:Doug Hele
1250:Designers
197:Luftwaffe
104:3 gallons
1272:Val Page
1046:C15 Star
965:B40 Star
844:A50 Wasp
791:A65 Star
681:Post-war
609:Archived
456:Archived
326:See also
263:and the
259:but the
253:Chertsey
251:, MVEE,
215:bakelite
160:Val Page
1614:Welbike
1599:BSA M20
1541:(15cwt)
1497:Guy Ant
1387:CMP FAT
1196:Model L
1118:Model E
1102:Pre-war
1089:Sunbeam
1066:Sunbeam
112:BSA M20
1215:250 cc
1189:350 cc
1170:Sloper
1153:500 cc
1144:M34-13
1139:M34-12
1134:M33-10
1127:600 cc
1111:770 cc
1084:Bantam
1077:stroke
1009:250 cc
975:B40 WD
953:350 cc
912:441 cc
815:500 cc
711:650 cc
690:750 cc
538:
513:
485:
403:
371:
304:Dallas
169:Sweden
72:stroke
58:Engine
1512:Mk II
1286:Other
1175:W33-7
177:India
82:Power
995:Fury
919:B 44
617:2009
590:2009
568:2009
536:ISBN
511:ISBN
483:ISBN
464:2009
438:2009
401:ISBN
369:ISBN
175:and
110:The
68:Bore
1237:C11
1222:B21
1160:M20
1075:Two
1041:C12
1036:C11
960:B31
893:M20
848:B33
1631::
822:A7
607:.
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