Motorworld’s newspaper №46
Letter from BMW confirming the production date of the motorcycle (March 03, 1928) and the date when it was shipped to a dealer in Danzig (April 25, 1928).
Having taken the 500-cc OHV engine from R37 as a basis, engineers added simplified frame and suspension and got rid of all electricals that were not mandatory. As a result, they were able to lower the motorcycle cost by 36% while keeping all of its racing ambitions, mostly thanks to the motor.
Horizontally-opposed OHV engine of R47 was analogous to the engine of the touring model R42, except that engine rating increased to 18 h.p. and maximum speed to 110 km/h. BMW sold 1720 R47 motorcycles (ten times more than R37), and many of these to German racing clubs.
One more reason for success was that BMW did not present the R47 as a racing-only motorcycle. This model was offered in a “basic” configuration, but when ordering the motorcycle, the client could choose from many optional offers, e.g. generator, horn and head light. A fuel tank of larger capacity was also offered as an option transferring this motorcycle to the sports and tourism class.
Model R47 occupies a place of honor among BMW motorcycles because it was truly advanced for its time. For example, roller bearers were used in it for the first time (in the design of the valve rocket arm), replaceable bushings and an innovative control system (except for manual shifting).
|Manufacturer||Bayerische Motoren Werke, AG (Germany)|
|Years of manufacture||1927-1928|
|Quantity produced, units||1 720|
|Price||1 850 RM|
|Today’s value||5373,81 $|
|ENGINE AND TRANSMISSION|
|Engine capacity, cc||494|
|Bore and stroke, mm||68 х 68|
|Engine rating||18 h.p. at 4000 rpm.|
|Carburetor||BMW Spezial 22 mm|
|FRAME AND WHEELBASE|
|Frame type||Duplex tubular|
|Front suspession||Leaf spring, 5 plates|
|Brakes||Front – drum-type, rear– foot brakes (on cardan shaft)|
|Wheel size||3.00х26 when using high-pressure tyres, 3.50х27 when using low-pressure tyres|
|Ground clearance, mm||
|Gas tank size, l||
|Maximum speed, km/h||