1952 BSA Bantam D1, 125cc.
SOLD
 
The Birmingham Small Arms Company Limited (BSA) was a major British industrial combine, a group of businesses manufacturing military and sporting firearms; bicycles and motorcycles to name a few.
Despite the Bantam being considered the archetypal 'truly British' lightweight motorcycle outselling all others, it was in fact based on a German design. The Bantam was based on the DKW RT 125.
This original Bantam, the D1, was released in October 1948 and continued in production for several years. It had telescopic forks, a rigid rear end, direct electrics, shovel front-mudguard and fishtail silencer, was available only in "mist green" and sold for £60 plus tax. Although the frame changed out of recognition (beginning with conversion to plunger and then swinging fork rear suspension), the engine remained a recognizable development of the original for the entire 23 years of production.
D1's were available with a variety of electrical lighting systems. Wipac systems were available either in 6v AC (known as direct lighting) or DC. The AC system used a small dry 'torch' cell battery to illuminate the forward facing 'pilot' bulb within the headlamp shell, the remaining lighting was only available for use when the engine was running and the dry cell had to be regularly replaced.
he D1 continued to be available to the public right up until 1963 and was still produced for the GPO (General Post Office) for at least 2 more years.
 
source: https://en.wikipedia.org/wiki/BSA_Bantam (edited and citations removed).