Year: 1950
Engine No; UYD-20001 / UYDL-101 (Lucas), YD-20001 / YDL-101 (Lucas)
Frame No; YD1-20001 (Rigid models) / YD1S-20001 (Plunger models)
CC: 125cc
Colours: As 1949.
Changes:
Bantam models from frame number YD24813 used an exhaust pipe being positioned over the rider footrest. Also, this year saw the introduction of the De-Luxe model with a Lucas generator and battery lighting system.
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Year: 1951
Engine No: YD1-40001 / YDL1-3001 (Lucas)
Frame No: YD1-40001 (Rigid models) / YD1S-40001 (Plunger models)
CC: 125cc
Colours: As 1949
Changes:
These used the Amal 361/1 carburettor, which replaced the 261/001D. The push-pull ‘hexagon for on’ fuel tap was replaced by the pull and turn type. The Geni-Mag was replaced by the Wico-Pacy series 55 Mk 8 Generator.
The De-Luxe model Bantam used an electrical horn as standard.
Year: 1952
Engine No: YD1-63001 (Wico-Pacy) / YD1L-8001 (Lucas)
Frame No: YD1-64001 (Rigid) / YD1S (Plunger)
CC: 125cc
Colours: As 1949
Changes:
The strength of steering headstock was improved, it also used a headlamp switch fitted to direct lighting models.
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Year: 1953
Engine No: BD2-101 (Wico-Pacy) / BD2L-101 (Lucas)
Frame No: BD2-101 (Rigid) / BD2S-101 (Lucas)
CC: 125cc
Colours: As 1949 / a black option was available.
Changes:
Wheel rims got a chrome-plated makeover, there was a dual seat option, & the pillion footrests were a standard fitting. A tubular type replaced the previous Bantam models flat type silencer. The crankcase screws were increased from 11 to 13.The De-Luxe Bantam D1 (Lucas) model was discontinued. It also used a new style front mudguard, using fixing mounts on the lower fork leg and was slim-valenced.
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Year: 1954
Engine No: D1 models: BD-101 (Direct & Comp) / BDB-101 (Battery) / D3 models: BD3-101 (Direct & Comp) / BD3B-101 (Battery)
Frame No: BD2-14600 (Rigid models) / BD2S-14600 (Plunger models)
CC: 125cc & 150cc
Colours: The D1 was as 1953. All wheel rims were chrome-plated, Pastel Grey with cream tank panels & Bantam Major tank transfers added. These also had the 'BSA Motorcycles' piled-arms transfers on the toolbox.
Changes:
The D1 had a headlamp cowl added; the D3 Bantam Major was introduced. The engines had larger fins added. There were heavier forks for the D3 models, rubber-damping tubes were added to all the forks. The rear stop/tail unit fitted to the battery models housed 3 bulbs. Right-hand side crank oil seal, which was positioned between the bearings, was altered and positioned against the flywheel.