BMW R47: history, specs, pictures
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.
|Production||1927 - 1928|
|Engine||two cylinder boxer, four-stroke|
|Bore / Stroke||68.0mm x 68.0mm|
|Top speed||68 mph (110 km/h)|
|Horse Power||17.57 HP (13.1 KW) @ 4000RPM|
|Fuel system||carburetor. 20mm bmw spezial|
|Ignition type||bosh magneto|
|Transmission||Gear box: 3-speed |
Final Drive: shaft drive (cardan)
|Suspension||Front: leading link |
|Brakes||Front: expanding brake (drum brake) |
|Wheelbase||55.51 inches (1410 mm)|
|Dimensions||L 82.68 inches (2100 mm)|
W 31.5 inches (800 mm)
H 37.4 inches (950 mm)
|Weight||(dry), 126.0 kg (wet)|
|Fuel capacity||3.7 Gallon (14.00 Liters)|
|Fuel consumption||3.00 liters/100 km (33.3 km/l or 78.41 mpg)|
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The BMW R47 was a two cylinder boxer, four-stroke standard produced by BMW between 1927 and 1928. It could reach a top speed of 68 mph (110 km/h). Claimed horsepower was 17.57 HP (13.1 KW) @ 4000 RPM.
The bike has a 3-speed transmission. Power was moderated via the dry-single plate-cable operated.
It came with a 3.50-27 front tire and a 3.50-27 rear tire. The front suspension was a leading link while the rear was equipped with a rigid. The R47 was fitted with a 3.7 Gallon (14.00 Liters) fuel tank. The wheelbase was 55.51 inches (1410 mm) long.