By the steering head reinforcing plate or front down tube. After frame the engine and frame markings were the same. Machines re- sating in were stamped vantam a 'Y' suffix to indicate that they were models and therefore eligible for the increased warranty. The engine is a unit construction engine and gearbox of one piece single cylinder 2 stroke. Up until it is rare for the engine and frame number to be identical and where the frame is shared by several models the codes start with the smallest model e. Use dmy dates from January Use British English from January Articles needing additional references from January All articles needing additional references Pages using deprecated image syntax All articles with unsourced statements Articles with unsourced statements from April Commons category link from Wikidata.
After dating and identifying many thousands of BSA's we have found that often a bike was built or shipped outside the dates given by the lettering system so this should only be used as a rough guide to the year and month of your machine.
DVLA & Machine Dating
Dating bsa bantam The front suspension of all D1's possessed no damping and resulted in a bouncy ride quality. Up until it is rare for the engine and frame number to be identical and where the frame is shared by several models the codes start with the smallest model e. This is just a guide and will fit most situations but frames were legitimately re- stamped by dealers if the original was damaged and a replacement fitted. Thunderbolt A65T - through all years. Archived from the original on 4 August Although the frame changed out of recognition beginning with conversion to plunger and then swinging fork rear suspensionthe engine remained a recognizable development of the original for the entire 23 years of production. The D1 the original model cc was available initially only with a rigid rear suspension, although within three years the range was enhanced to include an optional plunger rear suspension.