BMW R4 Series 1 (1932)

Technical Specifications
1932 BMW R4 Series 1
Engine
Engine type
Bore x Stroke
Displacement
Valves
Compression ratio
Max Power
Max Torque
Fuel system
Transmission
Final drive
Clutch
Ignition type
Starting system
Lubrication
Exhaust
Spark plug
Battery
Gear ratios

Air-cooled, 4-stroke, single cylinder vertical
84.0 x 78.0 mm (3.30 x 3.07 inches)
398 cc
OHV
5.7:1
12.0 HP @ 4000 rpm

1 x carburettor type SUM CK 3/500 Fr
3-speed
Shaft
Dry, single plate, cable operated
Battery ignition
Kick starter
Forced Feed Lubrication

Bosch W 175 or Bosch 200 G 24
Dimensions
Frame type
Castor
Overall length
Overall width
Overall height
Wheelbase
Seat height
Ground clearance
Dry weight
Fuel capacity
Colors
Suspension (front)
Suspension (rear)
Tyre (front)
Tyre (rear)
Brake (front)
Brake (rear)

Pressed steel duplex frame

1980 mm (77.95 inches)
850 mm (33.46 inches)
950 mm (37.40 inches)
1300 mm (51.11 inches)
828 mm (32.6 inches)
185 mm (7.3 inches)
137 kg
10 litres

Plate spring, 9 laminae, from July with friction shock absorber
Rigid
26x3.5 on 19x3
26x3.5 on 19x3
Drum brake 180 mm / 7.08 inches diameter
Drum brake 180 mm / 7.08 inches diameter

Image: http://www.bmbikes.co.uk