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An important development in the history of BMW's long-running flat-twin occurred in 1936 with the introduction of a welded, tubular steel frame on the R5 model, replacing the pressed steel chassis used hitherto. The R5's 500cc overhead-valve engine likewise was new and the following year a 600cc side valve derivative was introduced on the R6, a touring model intended for sidecar duty. In 1938 the R5 and R6 were updated, gaining a telescopic front fork and plunger rear suspension to become the R51 and R61, while the range was further extended by the introduction of a bored-out-to-750cc version of the latter – the BMW R71. The R71 engine only produced a relatively modest 22bhp but its biggest virtue was exceptional flexibility, which was just what its intended market required. Approximately 1,800 R71s had been made by the time production ceased in 1941. Post-war the design was revived in the USSR as the Ural.

In Media[edit | edit source]

BMW R71 in Media

Also called R 71
Production 1938 - 1941
Class Classic
two cylinder boxer, four-stroke
Bore / Stroke 78.0mm x 78.0mm
Compression ratio 5.5:1
Top Speed 78 mph (125 km/h)
Horsepower 21.59 HP (16.1 KW) @ 4600RPM
Transmission Gear box: 4-speed

Final Drive: shaft drive (cardan)

Clutch: dry-single plate-cable operated
Suspension Front: cartridge
Rear: twin shock-swingarm
Brakes Front: expanding brake (drum brake). single
Rear: expanding brake (drum brake)
Front Tire 3.5-19
Rear Tire 3.5-19
Wheelbase 55.12 inches (1400 mm)
Length 83.86 inches (2130 mm)
Width 32.09 inches (815 mm)
Height 37.8 inches (960 mm)
Weight 187.0 kg (wet)
Fuel Capacity 3.7 Gallon (14.00 Liters)
Fuel Consumption 4.50 liters/100 km (22.2 km/l or 52.27 mpg)
Manuals Service Manual

The BMW R71 was a two cylinder boxer, four-stroke Classic motorcycle produced by BMW between 1938 and 1941. It could reach a top speed of 78 mph (125 km/h). Claimed horsepower was 21.59 HP (16.1 KW) @ 4600 RPM.

Engine[edit | edit source]

The engine was a air cooled two cylinder boxer, four-stroke. A 78.0mm bore x 78.0mm stroke result in a displacement of just 746.0 cubic centimeters. Fuel was supplied via a overhead valves (ohv).

Drive[edit | edit source]

The bike has a 4-speed transmission. Power was moderated via the dry-single plate-cable operated.

Chassis[edit | edit source]

It came with a 3.5-19 front tire and a 3.5-19 rear tire. Stopping was achieved via expanding brake (drum brake). single in the front and a expanding brake (drum brake) in the rear. The front suspension was a cartridge while the rear was equipped with a twin shock-swingarm. The R71 was fitted with a 3.7 Gallon (14.00 Liters) fuel tank. The wheelbase was 55.12 inches (1400 mm) long.

1938 - 1941 BMW R 71[edit | edit source]

1938 - 1941 BMW R 71

The 1938 BMW R 71 is one of the most powerful machines designed by the House of Munich up to date. It sports an air-cooled, four-stroke, 746cc, boxer twin cylinder powerhouse mated to a four-speed manual transmission and can produce a claimed 22 horsepower at 4600 rpm. Standard features include full-fenders, a rear, fender-mounted luggage rack, laced wheels, a dual exhaust system, a telescopic front fork, plunger shocks, a sprung single seat and a large, round headlight. In addition, it can be fitted with a sidecar.

In Media[edit | edit source]