BMW R47
BMW R47 | |
Manufacturer | |
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Production | 1928 |
Class | Classic |
Engine | air-cooled, four-stroke, boxer twin cylinder, OHV |
Bore / Stroke | 68.6mm x 68.6mm |
Compression ratio | 5.8:1 |
Top Speed | 68 mph (110 km/h) |
Horsepower | 17.57 HP (13.1 KW) @ 4000RPM |
Transmission | Gear box: 3 speed, manual Clutch: dry, single plate |
Final Drive | shaft drive (cardan) |
Suspension | Front: plate spring, 5 laminae Rear: hard-tail, sprung seat |
Brakes | Front: 150mm drum Rear: external shoe brake at the 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 | 30.98 inches (787 mm) |
Height | 37.4 inches (950 mm) |
Weight | 130.0 kg (wet) |
Fuel Capacity | 3.7 Gallon (14.00 Liters) |
Manuals | Service Manual |
The BMW R 47 was a air-cooled, four-stroke, boxer twin cylinder, OHV Classic motorcycle produced by BMW in 1928. Claimed horsepower was 17.97 HP (13.4 KW) @ 4000 RPM.
BMW's first sports model, the BMW R37, appeared in 1924, joining the original BMW R32 tourer. The BMW R37 boasted a new overhead-valve engine producing 16bhp, almost double the R32's power output, but was produced for little more than a year before being replaced by the improved BMWR47. The latter was introduced in 1926 alongside the sidevalve-engined R42 tourer, both models benefiting from a redesigned and more powerful engine boasting detachable alloy cylinder heads and cooling fins set at 90 degrees to the cylinder axis. The engine was set further back in the duplex loop frame, which improved weight distribution and enabled straight front down-tubes to be used. The braking too came in for attention: the old block-and-pulley type rear brake being replaced by a drum on the driveshaft gripped by external contracting bands. Electric lighting was still regarded as an 'extra' and would not be standardised until 1928. Maximum power output of the R47 was 18bhp and its top speed in the region of 70mph (113km/h). R47 production lasted for just two years, 1,720 machines being sold.
Engine[edit | edit source]
A 68.6mm bore x 68.6mm stroke result in a displacement of just 494.0 cubic centimeters.
Drive[edit | edit source]
The bike has a 3 speed, manual transmission. Power was moderated via the dry, single plate.
Chassis[edit | edit source]
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 the 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.
1928 BMW R 47[edit | edit source]
The House of Munich has launched the 1927 R 47 with an air-cooled, four-stroke, 494cc, boxer twin cylinder powerplant mated to a three-speed manual transmission, that could produce a claimed 18 horsepower at 4000 rpm. It comes with a front drum brake, a plate spring fork, a hard-tail rear suspension, a single sprung seat, a rear luggage rack, pull-back handlebars, laced wheels, long fenders, and a small luggage rack in the front.
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