BMW R 47

BMW R 47 Date 1927-1928

Number sold 1.720

Price 1.850,- RM

Engine

internal designation M 51
engine type four-stroke two-cylinder flat-twin
Bore/stroke 68 x 68 mm
Cubic capacity 494 cm3
Max power 18 PS at 4000 U /min
Compression ratio 5,8 : 1
Valves per cylinder ohv
Carburation system 1 carburettor, Typ BMW Spezial two-valve 22 mm
Engine lubrication forced-feed lubrication
oil pump gear pump

 
Power transmission

 
Clutch single discs, dry
Number of gears 3
shifting manual
Gear ratios 2,5 / 1,5 / 1,07
Rear wheel ratio 1 : 4,38 (with sidecar 1 : 5,7)
Bevel/crown wheel 13 / 57 teeth (with sidecar 10 / 57)

 
Electrical system

Alternator magneto generator on request
Ignition Bosch magneto ignition
Spark plugs Bosch W 175

 
Suspension

designation R 47
Type of frame twin-loop steel tubular frame
Front suspension plate spring, 5 laminae
Rear suspension rigid
wheel rims CC 1
Tyres front 27 x 3,5 low pressure or 26 x 3 high pressure
Tyres rear 27 x 3,5 low pressure or 26 x 3 high pressure
Brakes front drum brake 150 mm
Brakes rear external shoe brake at the gearing (on cardan shaft)

 
Dimensions and weights

Length x width x height 2100 x 800 x 950 mm
Wheel base 1410 mm
Tank capacity 14 l
Unladen weight, full tank 130 kg (with Original-sidecar 192 kg)
load rating k.A.
Top speed 110 km/h