BMW R42

The BMW R 42 was a air-cooled, four-stroke, boxer twin cylinder, SV Classic motorcycle produced by BMW in 1926. Claimed horsepower was 11.94 HP (8.9 KW) @ 3400 RPM.

BMW R42
Manufacturer	BMW
Production	1926 - 1928
Class	Classic
Engine	air-cooled, four-stroke, boxer twin cylinder, SV
Bore / Stroke	68.6mm x 68.6mm
Compression ratio	4.9:1
Top Speed	59 mph (95 km/h)
Horsepower	11.67 HP (8.7 KW) @ 3400RPM
Fuel System	carburetor. 20mm BMW spezial
Transmission	Gear box: 3 speed, manual Final Drive: shaft Clutch: dry, single plate
Suspension	Front: plate spring, 5 laminae Rear: hard-tail, sprung seat
Brakes	Front: 150mm drum Rear: external shoe brake at gearing (on cardan shaft)
Front Tire	27 x 3.5
Rear Tire	27 x 3.5
Wheelbase	55.51 inches (1410 mm)
Length	82.68 inches (2100 mm)
Width	31.5 inches (800 mm)
Height	37.4 inches (950 mm)
Weight	126.0 kg (wet)
Manuals	Service Manual

Engine

A 68.6mm bore x 68.6mm stroke result in a displacement of just 494.0 cubic centimeters.

Drive

The bike has a 3 speed, manual transmission. Power was moderated via the dry, single plate.

Chassis

It came with a 27 x 3.5 front tire and a 27 x 3.5 rear tire. Stopping was achieved via 150mm drum in the front and a external shoe brake at gearing (on cardan shaft) in the rear. The front suspension was a plate spring, 5 laminae while the rear was equipped with a hard-tail, sprung seat. The wheelbase was 55.51 inches (1410 mm) long.

1926 - 1928 BMW R 42

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  1926 - 1928 BMW R 42

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  1926 - 1928 BMW R 42

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  1926 BMW R42

The R 42 from the House of Munich had, at its heart, an air-cooled, four-stroke, 494cc, boxer twin cylinder engine mated to a three-speed manual transmission, and could reach a claimed maximum power output of 12 horsepower at 3400 rpm. Standard features included laced wheels, long fenders, a small headlamp, wide handlebars, a plate string front fork, a rigid rear suspension with a sprung seat, a rear luggage rack that could be transformed in a passenger seat, and a front drum brake.