Motorworld’s newspaper №46

The main task for BMW in the 1920s was creating a powerful motorcycle for mass production. After a thorough analysis of the project development for model R37 which was a powerful, yet a complex and expensive machine, German engineers arrived at a great solution. The key to success of the new motorcycle that was assigned the index R47 was the reduction of process costs.

BMW R47 в полной комплектации

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
Type Twin-cylinder, horizontally-opposed
Engine capacity, cc 494
Bore and stroke, mm 68 х 68
Engine rating 18 h.p. at 4000 rpm.
Sparking Bosch magneto
Carburetor BMW Spezial 22 mm
Battery 6 V
Clutch Single-plate, dry
Transmission 3-speed
FRAME AND WHEELBASE
Frame type Duplex tubular
Front suspession Leaf spring, 5 plates
Rear suspension Rigid
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
Dimensions
Length, mm
2 100
Width, mm
   800
Height, mm
   950
Wheelbase, mm
1 410
Ground clearance, mm
   110*
Seat height
   760*
Mass, kg
   130
Gas tank size, l
     14
Maximum speed, km/h
   110
Range, km

* – Data on the results of metering at the exhibit “Motorworld by V.Sheyanov”.


Books:

PDF

Exploitation guide BMW R47 (ger.)