D1 Bantams produced from 1948 to 1963 the longest production run of any model. Originally manufactured as a 123cc engine only, the first complete bikes did not appear until the end of 1948. Available in either rigid or plunger formats. Probably the most recognisable of all Bantams.
The bike featured is a 1954 plunger model purchased as a restoration project. This model is fitted with the first of the larger fin barrels with a 55mm stud pitch common to both the 125cc and 150cc, the previous year was the first large fin engines but had a 53mm pitch, the earlier bikes having the pineapple smaller fin engines.
The 1954 models carried a new frame number sequence BD2s so are sometimes referred to as D2 bantams but as this same frame number sequence was also used on the plunger D3 it is debatable if the D2 designation was in fact used by BSA.