All BSA parallel twins were pushrod operated overhead valve machines.The A7 and A10 models were semi-unit construction until about 1953 and pre-unit construction thereafter.As classic bikers ourselves, we understand what you need, and we pride ourselves on the personal service that we are able to offer our customers.
On this page you will find Triumph, BSA, and Norton engine and frame serial numbers.
Owners with late model BSA's can easily identify the month and year of their machine as the factory adopted a dating system for frame and engine numbers for the 1969 season models.
As with all previous BSA seasons the model year started after the factory shutdown in July so that 1969 models were those made from August 1968, through to July 1969.
In the 1930s the M series was a mixture of overhead valve and side-valve models.
During and after the Second World War only the side-valve models of this series were continued, typically for use by the armed forces or in sidecar combinations.