BMW R20

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BMW R20


Motorcycles displacing less that 200cc did not have to be licensed in Germany during the early 1930s and thus the category was an important one for all domestic manufacturers. Lightweight two-strokes dominated this sector of the market, which BMW contested with the BMW R2. Launched early in 1931, the relatively expensive four-stroke R2 sold well despite the difficult trading conditions. The 198cc overhead-valve engine was housed in a pressed-steel frame similar in design to that of the twins, and like its larger brethren the single employed shaft final drive. Various improvements were made over the next few years as the R2 progressed through Series 1 to 5. Developed from the best-selling R2, the 192cc R20 was produced during 1937/38, 5,000 examples being sold. The newcomer was powered by a revised 192cc overhead-valve engine producing 8bhp, which was housed in a frame made from bolted-up steel tubes and equipped with an un-damped telescopic front fork. Weight with a full tank of fuel was 286lbs (130kg) and the top speed 59mph (95km/h).

BMW R20
Manufacturer BMW
Also called R 20
Production 1937 - 1938
Class Classic
Engine single cylinder, four-stroke
Bore / Stroke 63.0mm x 64.0mm
Compression ratio 6.0:1
Top speed 59 mph (95 km/h)
Horse Power 7.91 HP (5.9 KW) @ 5400RPM
Ignition type battery
Battery 6.1:1
Transmission Gear box: 3-speed

Final Drive: shaft drive (cardan)

Clutch: dry-multiplate-cable operated
Suspension Front: telescopic fork
Rear: rigid
Brakes Front: expanding brake (drum brake)
Rear: expanding brake (drum brake)
Front Tire 2.99-19
Rear Tire 2.99-19
Wheelbase 52.36 inches (1330 mm)
Dimensions L 78.74 inches (2000 mm)
W 31.5 inches (800 mm)
H 35.43 inches (900 mm)
Weight  (dry), 130.0 kg (wet)
Fuel capacity 3.17 Gallon (12.00 Liters)
Manuals Service Manual
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The BMW R20 was a single cylinder, four-stroke Classic motorcycle produced by BMW between 1937 and 1938. It could reach a top speed of 59 mph (95 km/h). Claimed horsepower was 7.91 HP (5.9 KW) @ 5400 RPM.

Engine[edit]

The engine was a air cooled single cylinder, four-stroke. A 63.0mm bore x 64.0mm stroke result in a displacement of just 192.0 cubic centimeters. Fuel was supplied via a overhead valves (ohv).

Drive[edit]

The bike has a 3-speed transmission. Power was moderated via the dry-multiplate-cable operated.

Chassis[edit]

It came with a 2.99-19 front tire and a 2.99-19 rear tire. Stopping was achieved via expanding brake (drum brake) in the front and a expanding brake (drum brake) in the rear. The front suspension was a telescopic fork while the rear was equipped with a rigid. The R20 was fitted with a 3.17 Gallon (12.00 Liters) fuel tank. The wheelbase was 52.36 inches (1330 mm) long.

1938 - 1940 BMW R 20[edit]

1938 - 1940 BMW R 20 1938 - 1940 BMW R 20

The 1938 BMW R 20 has, at its heart, an air-cooled, four-stroke, 192cc, single cylinder lump paired to a three-speed manual transmission and can reach a maximum power output of 8 horsepower at 5400 rpm. It also comes with laced wheels, a rear luggage rack, a large, round headlamp, a telescopic front fork, a hard-tail rear suspension with a sprung seat, a drum braking system and full fenders.


In Media[edit]