BSA 1970s

BSA B50 Serial Numbers 1969-1973

B50 Engine Numbers

BSA used a new coding system for frames and engines from 1969 until the end in 1973

This consisted of three parts:

  1. The model code
  2. Two letters giving month and year respectively
  3. A five digit number

Both engine and frame received the same markings. 

The engines was built, given a number and then stored ready for the frame. This would be the B50SSHE part of the serial code denoting a B50SS engine for July 1971. When the frame was manufactured it would be given a unique number in that 'manufacturing year' range ie: 15222. The Engine and Frame numbers were matching so these two, Code/Number, would be brought together at assembly and the finished serial number completed.

The Serial Number followed the Model Type hence B50SSHE15222 denoted a B50SS
The two letters following the model type denotes the Month & Year of manufacture. HE denotes July 1971

To find out the details from your code. 
Enter the Two Letters into the 'Code' box & click the Submit button.
Code          Your Engine was manufactured in           

The BSA 'manufacturing year' ran from August to July. 

At BSA the model year started after the factory shutdown in July so that 1971 models were those made between August 1970 through to July 1971. 

The date letters are as follows :-

1st Letter 2nd Letter
A = January : C = 1969
B = February : D = 1970
C = March : E = 1971
D = April : G = 1972
E = May : H = 1973
G = June : J = 1974
H = July :
J = August :
K = September :
N = October :
P = November :
X = December :

The numbering started at the beginning of each season and always started at 00100 leaving the first 99 for experimental use. The numbers were consecutively allocated throughout a model range so the B25 & B50 are intermingled. 

Gold Star 250 B25SS   1971
Victor 250 B25T         1971
Gold Star 500 B50SS   1971 to 1972
Victor 500 B50T         1971 to 1972
Victor MX B50MX        1971 to 1973

Note: The lettering system should just be taken as a rough guide.

 

 

See also 1971 B25 B50 Catalogue

Source: Adapted from a page at the Cedric Norman Archive