History of the BSA Bantam

The birth of the BSA Bantam did not take place in England, the origins were in a pre-war Germany design, the DKW RT125. As part of the war reparations, Germany paid after the conclusion of WWII. The design was taken by the allies. This same design was also copied by Harley-Davidson, Yamaha, WSK (Poland), Voskhod (Russia) & MZ who took over the old DKW factory in East Germany.

BSA reversed the entire engine design, creating a mirror image of the original. This was done to move the shifter & kickstart over to the right side, converting it from metric to inches, as well as incorporating British electrics.

Originally produced as a 'Motor unit' only (for export in order to boost revenue for the UK) it was rapidly incorporated into a frame and what emerged was the 1948 BSA D1 Bantam. It shared the 58mm stroke, common to all Bantams and with it's 52mm bore, it displaced 123cc. The conventional 2-stroke single was unit-construction with a 3-speed gearbox. At the time of it's launch, it was a thoroughly modern engine.

When first produced, the 1948, D1 Bantam with rigid frame & electrics was the only model. It was produced through to 1955. However, by 1950, the model-range began to widen & deepen. The D1 became available in either rigid or plunger frame, Wipac or Lucas electrics as well as a  competition version with rigid or plunger, and Lucas, Wipac, dry cell or no electrics. The D1 came in 8 model variations at one time or another.

The BSA Bantam proved popular around the world. It was tough and stood up to the punishing environment in the various countries of the British Empire. It handled well, had good brakes and it was comfortable.

As the model evolved, there was a quest for more power, through more displacement. By enlarging the bore to 57mm, BSA created the 148cc Bantam D3 in 1954. There were two road models with plunger rear suspension and either direct or battery lighting. Competition models offered the option of either a rigid or plunger frame. D3's also had a more robust front fork than the D1. Starting in 1956, all BSA Bantams went with a new frame with swingarm rear suspension.

In 1957, to meet the quest for more power, BSA enlarged the Bantam again, this time boring it out to 61.5mm creating the 172cc BSA Bantam D5. The D5 got a new barrel with flange-mounted carb, bigger (wider) brakes & 3.00 X 18" tires.

The D5 was replaced in 1959 by the D7. Remaining at 175cc, it was a refinement on the D5 and was listed in the 1959 catalog as 'The Super' The engine had a new cover on the left to enclose both the magneto and the clutch adjuster. Hydraulically-damped front forks, a headlight nacelle & larger brakes were also evident.

At the beginning of the 1960's, BSA continued to produce both 175 Bantam D7 Supers and the 125 Bantam D1. However, with the invasion of Japanese bikes into British market, there was a demand for more from a motorcycle. In 1963 BSA dropped the ancient D1 the Bantam D7 went upscale with it's DeLuxe version,with the economy model becoming the D7 Silver.

July 1966, saw the replacement of the Bantam D7 by the substantially upgraded Bantam D10. Significant changes were made to the engine, it's electrics were also vastly improved. Early D10s were produced with Monobloc carburettors, but quickly changed over to Amal Concentric. Which when coupled with a higher compression ratio, produced more power. An additional plate was added to the clutch to cope. The D10 Silver and D10 Super retained the old 3-speed gearbox from the D7 but the new BSA Bantam D10 Sports & D10 Bushman now had a new 4-speed gear box.

The D10 was replaced by the D14 series in 1968, which all came with 4-speeds and a larger exhaust. The line up of models were the Supreme being replaced by the D14/4, the Sports by the D14/4S and the Bushman by the D14/4B.

In 1969, BSA replaced these D14 Bantam models with just two: The D175 road version and the D175 Bushman, a revised engine with new crankcase castings, a new cylinder head with central plug.

With Japanese bikes flooding the market, the BSA Bantam entered the 1970s with only the standard D175 road version. In 1971, like most classic British motorcycles, at that time it failed to keep up with rapidly changing times, until it was left behind by progress. Amid financial difficulties, production of the BSA Bantam ceased after 23 years. The demise of the Bantam was shortly followed by the folding of BSA, along with  many of the other leading manufacturers of British motorcycles which once dominated the world's motorcycle industry.