BMW R 4 series 4

BMW R 4 series 4 Date 1935

Number sold 3.651

Price 1.150,- RM

Engine

Internal Designation M 69 S 4
Engine type four-stroke vertical single cylinder engine
Bore/stroke 84 x 78 mm
Cubic capacity 398 cm3
Max power 14 PS at 4000 rpm
Compression ratio 5,7 : 1
Valves per cylinder ohv
Carburation system 1 carburettor Typ SUM CK 3/500 Fr
Engine lubrication forced-feed lubrication
Oil pump gear pump

Power transmission

Clutch single discs, dry
Number of gears 4
Shifting manual (Tankkulisse)
Gear ratios 3,6 / 2,18 / 1,35 / 1,1
Rear wheel ratio 1 : 5,11 (with sidecar 1: 5,63)
Bevel/crown wheel 9 / 46 teeth (with sidecar (8 / 45)

Electrical system

Alternator Bosch, 45 W / 6 V
Ignition battery ignition
Spark plugs Bosch DM 175/1

Suspension

Designation F 69 S 4
Type of frame pressed steel duplex frame
Front suspension plate spring, 9 laminae mit 2 Stoßdämpfern
Rear suspension rigid
wheel rims 26 x 3,5
Tyres front 26 x 3,5 SS
Tyres rear 26 x 3,5 SS
Brakes front drum brake Ø 180 mm
Brakes rear drum brake Ø 180 mm

Dimensions and weights

Length x width x height 1980 x 850 x 950 mm
Wheel base 1300 mm
Tank capacity 12 l
Unladen weight, full tank 137 kg
permitted loading 200 kg
Fuel consumption ca. 3,5 l / 100 km
Oil consumption ca. 1 - 2 l / 1000 km
Top speed 100 km/h

Back to index