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BSA Bantam
The BSA Bantam is a two-stroke unit construction motorcycle that was produced by the Birmingham Small Arms Company (BSA) from 1948 (as a 123 cc) until 1971 (as a 173 cc). Exact production figures are unknown, but it was between 350,000 and 500,000.
The Bantam was based on a German design, the DKW RT 125, which the Allies of World War II received as war reparations. BSA launched the first model, the D1, in 1948. Motorcycles based on the RT 125 also went into production in other countries. The DKW factory was in Zschopau in the Soviet occupation zone in Germany, and in about 1946 the Soviet Union launched the Moskva M1A made in Moscow.[citation needed] Harley-Davidson launched its Model 125 late in 1947. Auto Union, DKW's parent company, was re-founded in Ingolstadt in the American occupation zone in Germany, and resumed RT 125 production in 1949. The former DKW factory in Zschopau became part of IFA, which resumed RT 125 production in 1950. The Zschopau factory later became MZ[citation needed] In 1955 Yamaha launched its YA-1, which was its first production motorcycle.[citation needed]
BSA built the Bantam in Redditch. It was designed as a mirror image of the RT 125, so that the gearchange was on the right side, in conformity with other British motorcycles of the period, and with measurements changed from metric to inches. The model Bantam, the D1, was launched in 1948 outside of the UK and in 1949 within the UK. It was in production until 1963. It had a three-speed gearbox, and a telescopic front fork with undamped springs. In its original form the D1 had no rear suspension; "direct" electrics; and a "fishtail" silencer. The front mudguard was deeply valanced, to allow for the fact that it was fitted to the "unsprung" part of the front fork, meaning that the front wheel moves up and down within the mudguard. At first the D1 was offered in only one colour, Mist Green, with an ivory panel painted on each side of the fuel tank. It was priced at £60 plus purchase tax.
In subsequent years BSA developed the Bantam with battery electrics; damped front suspension; rear suspension with plungers, and then with a swinging arm; larger engines; a steel silencer that could be dismantled for cleaning; and a four-speed gearbox. Models from 1959 onward have a swinging arm frame that bears little relation to the rigid, plunger and initial swinging-arm versions. However, the form of the original engine remained recognisable throughout the 23 years of Bantam production.
The engine is a unit-construction (engine and gearbox of one piece) single-cylinder two-stroke. The barrel is cast iron and the cylinder head is alloy. Models built from 1948 until 1968 have a three-speed gearbox. Models from 1968 to 1971 have a four-speed gearbox. All models have a "wet" clutch.
Ignition is of two types: a Lucas battery-powered coil in earlier machines, or a Wipac magneto. The magneto is on a composite assembly within the flywheel with its magnet inserts. Windings give power either directly to the lights (with a dry cell for when the engine was stopped) or via a rectifier to a lead-acid battery. Early D1s have a "fishtail" style silencer. This was hard to clean inside, which was problematic for a two-stroke. On later D1s BSA fitted a more conventional cylindrical silencer, from which the baffles can easily be removed for cleaning. High-level exhausts were made for the trials and off-road models, in which the only electrics are the magneto-powered ignition.
This listing shows only the main variants and most models were available with refinements or in competition form. BSA had used a lettering system for their range of motorcycles and started the "D" series for their first two-stroke. The D175 was marketed as the B175 as BSA struggled against imports in the late 60s to its closure in 1972 (the larger capacity "B" series having helped make them the largest motorcycle manufacturer in the world). The engine size shown is nominal, British motorcycles were made 1 or 3 cc smaller than their tax bracket maximum to allow for re-bores and wear.
Pre-1958 (D1 to D3) had 19 inch wheels and 4.5 inch brakes. The 1958 D5 had 18 inch wheels and 4.5 inch brakes. 1959 D7 and later models had 18 inch wheels and 5 inch brakes front and rear.
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BSA Bantam
The BSA Bantam is a two-stroke unit construction motorcycle that was produced by the Birmingham Small Arms Company (BSA) from 1948 (as a 123 cc) until 1971 (as a 173 cc). Exact production figures are unknown, but it was between 350,000 and 500,000.
The Bantam was based on a German design, the DKW RT 125, which the Allies of World War II received as war reparations. BSA launched the first model, the D1, in 1948. Motorcycles based on the RT 125 also went into production in other countries. The DKW factory was in Zschopau in the Soviet occupation zone in Germany, and in about 1946 the Soviet Union launched the Moskva M1A made in Moscow.[citation needed] Harley-Davidson launched its Model 125 late in 1947. Auto Union, DKW's parent company, was re-founded in Ingolstadt in the American occupation zone in Germany, and resumed RT 125 production in 1949. The former DKW factory in Zschopau became part of IFA, which resumed RT 125 production in 1950. The Zschopau factory later became MZ[citation needed] In 1955 Yamaha launched its YA-1, which was its first production motorcycle.[citation needed]
BSA built the Bantam in Redditch. It was designed as a mirror image of the RT 125, so that the gearchange was on the right side, in conformity with other British motorcycles of the period, and with measurements changed from metric to inches. The model Bantam, the D1, was launched in 1948 outside of the UK and in 1949 within the UK. It was in production until 1963. It had a three-speed gearbox, and a telescopic front fork with undamped springs. In its original form the D1 had no rear suspension; "direct" electrics; and a "fishtail" silencer. The front mudguard was deeply valanced, to allow for the fact that it was fitted to the "unsprung" part of the front fork, meaning that the front wheel moves up and down within the mudguard. At first the D1 was offered in only one colour, Mist Green, with an ivory panel painted on each side of the fuel tank. It was priced at £60 plus purchase tax.
In subsequent years BSA developed the Bantam with battery electrics; damped front suspension; rear suspension with plungers, and then with a swinging arm; larger engines; a steel silencer that could be dismantled for cleaning; and a four-speed gearbox. Models from 1959 onward have a swinging arm frame that bears little relation to the rigid, plunger and initial swinging-arm versions. However, the form of the original engine remained recognisable throughout the 23 years of Bantam production.
The engine is a unit-construction (engine and gearbox of one piece) single-cylinder two-stroke. The barrel is cast iron and the cylinder head is alloy. Models built from 1948 until 1968 have a three-speed gearbox. Models from 1968 to 1971 have a four-speed gearbox. All models have a "wet" clutch.
Ignition is of two types: a Lucas battery-powered coil in earlier machines, or a Wipac magneto. The magneto is on a composite assembly within the flywheel with its magnet inserts. Windings give power either directly to the lights (with a dry cell for when the engine was stopped) or via a rectifier to a lead-acid battery. Early D1s have a "fishtail" style silencer. This was hard to clean inside, which was problematic for a two-stroke. On later D1s BSA fitted a more conventional cylindrical silencer, from which the baffles can easily be removed for cleaning. High-level exhausts were made for the trials and off-road models, in which the only electrics are the magneto-powered ignition.
This listing shows only the main variants and most models were available with refinements or in competition form. BSA had used a lettering system for their range of motorcycles and started the "D" series for their first two-stroke. The D175 was marketed as the B175 as BSA struggled against imports in the late 60s to its closure in 1972 (the larger capacity "B" series having helped make them the largest motorcycle manufacturer in the world). The engine size shown is nominal, British motorcycles were made 1 or 3 cc smaller than their tax bracket maximum to allow for re-bores and wear.
Pre-1958 (D1 to D3) had 19 inch wheels and 4.5 inch brakes. The 1958 D5 had 18 inch wheels and 4.5 inch brakes. 1959 D7 and later models had 18 inch wheels and 5 inch brakes front and rear.