B Single - B31 & B33
BSA used a system of letters and numbers for yearly identification of their machines. This information combined with the yearly numbers below should help you identify the year and model of your machine. The Frame Numbers are alway stamped. If you find raised numbers, these are casting part numbers. British 1942 BSA Paratrooper Bicycle, Serial Number R3641, above photo. The Birmingham Small Arms Company was contracted by British Government during WWII to produce a folding bicycle for the Army for use by paratroopers. Shown here is the very early first model BSA Paratroop Bicycle.
Mansell-Jones, 'Sunnyside,' Lodge Road, Croydon, Surrey, Patent No.Weight 10 lbs. Presented by Harry Green. Two earlier patents by the same inventor, Nos. And 7141/1899, show a similar result achieved by a system of spring-controlled toggles, which allowed the ends of the seat-stays to rise and fall, and the rear end of the. BSA Ladybird gives your dreams wings on two wheels. With a BSA Ladybird by your side, every moment becomes joyous, exciting and amusing. Each ride is fun, comfortable and secure with the exciting new range of colourful and feature loaded bicycles. These bicycles enable you to explore the world fearlessly with confidence. Engine number prefixes - Identification BRASS PLATE NUMBERS EXPLAINED BSA WD B40 Contract numbers AUSTRALIAN B40 AWD - GA WD B40 Prototype Early BSA WD B40 B40 Military Mk2 and Roughrider By Rupert Ratio Mitchell Collection Bike 1 BSA WD B40 Mk1 1967 Mitchell Collection Bike 2 BSA WD B40 Mk1 1967 Mitchell Collection bike 3 BSA WD B40 GR Mk1.
Year B31 Engine B33 Engine
1946 XB31-101 XB31-101
1947 XB31-101 XB33-101
1948 YB31-101 YB33-101
1949 ZB31-101 ZB33-101
1950 ZB31-9001 ZB33-4001
1951 ZB31-15001 ZB33-7001
1952 ZB31-21001 ZB33-11001
1953 BB31-101 BB33-101
1954 BB31-6001 BB33-2001
1955 BB31-15001 BB33-5001
1956 BB31-22001 BB33-7301
1957 BB31- BB33-
1958 GB31-101 GB33-101
1959 GB31-1909 GB33-662
1960 GB33-1001
Year Rigid Frame Spring Frame
1946
1947 XB31-101
1948 YB31-101
1949 ZB31-101 ZB31S-101
1950 ZB31-9001 ZB31S-5001
1951 ZB31-14001 ZB31S-10001
1952 ZB31-19001 ZB31S-17001
1953 BB31-101 BB31S-101
1954 BB31-1386 BB31S-5895
CB31-101
1955 BB31S-12001
CB31-6001
1956 EB31-101
1957 EB31-
1958 FB31-101
1959 FB31-2572
1960 GB33-101
A Unit Twins, 1962-65
Model 1962 Eng./Frame
A50 A50-101/A50-101
A65 A65-101/A50-101
Model 1963 Eng./Frame
A50 A50-823/A50-2288
A65 A65-1947/A50-2288
Model 1964 Eng./Frame
A50 A50A-101/A50-5501
A50 (Police) A50AP-101/A50-5501
A50C (USA) A50B-101/A50B-101
A65 A65A-101/A50-5501
A65 (Police) A65AP-101/A50-5501
A65R A65B-101/A50-5501
A65R (Tach) A65C-101/A50-5501
A65T/R A65B-101/A50-5501
A65L/R A65D-101/A50B-101
A65SH A65E-101/A50B-101
Model 1965 Eng./Frame
A50 A50A-686/A50-8437
A50 (Police) A50AP-121/A50-8437
A50C (US) A50D-101/A50B-4001
A50CC (US) A50B-507/A50B-4001
A50C (UK) A50DC-101/A50B-4001
A50CC(UK)A50DC-101/A50B-4001
A65 A65A-1134/A50-8437
A65 (Police) A65AP-267/A50-8437
A65R A65B-334/A50-8437
A65R (Tach) A65C-1082/A50-8437
A65L/R A65D-1742/A50B-4001
A65SH A65E-701/A50B-4001
A65L A65DC-2158/A50B-4001
A65LC A65DC-2158/A50B-4001
A Unit Twins, 1966-69
1966 Engine
A50 Royal Star A50R-101
A50 Wasp A50W-101
A65 Thunderbolt A65T-101
A65 Lightning A65L-101
A65 Hornet A65H-101
A65 Spitfire A65S-101
Frame No. - All A50C-101
1967 Eng. & Frame
A50 Royal Star A50RA-101
A50 Wasp A50WA-101
A65 Thunderbolt A65TA-101
A65 Lightning A65LA-101
A65 Hornet A65HA-101
A65 Spitfire A65SA-101
1968 Eng. & Frame
A50 Royal Star A50RB-101
A50 Wasp A50WB-101
A65 Thunderbolt A65TB-101
A65 Lightning A65LB-101
A65 Firebird A65FB-101
A65 Spitfire A65SB-101
1969 Eng. & Frame
A50 Royal Star A50RC-101
A65 Thunderbolt A65TC-101
A65 Lightning A65LC-101
A65 Firebird A65FC-101
Models 1969 On
The engine number is located on the left side of the engine, immediately below the cylinder barrelflange. The number is stamped onto a raised pad.The frame number is located for BSA's 1969 and earlier on the left side of the frame, on the frontengine mounting lug. BSA's 1971 and later, either side of the frame on the stearing head to framegusset, note that these don't always have the model stamped.On'71 up, 250-500 single oil in frame bikes, the number is located on the kickstand lug or steering head area on late bikes.The Number consists of 4 sections.
The first letter indicates
the month of manufacture.
A = January
B = February
C = March
D = April
E = May
G = June
H = July
J = August
K = September
N = October
P = November
X = December
Bsa Bicycle Serial Numbers Database
The second letter indicates
the year of manufacture.
C = 1969
D = 1970
E = 1971
G = 1972
H = 1973
The third section is a numerical block of five figures which commence with engine number 00100.
The fourth section indicates the model. I have seen this section placed first on the pad as well.
Example 2
Model Month Year Number
A65T N D 00100
