Information kindly supplied by P.Hawksley

www.bmbikes.co.uk

Start of Production

1936



Click to View Available Literature

End of Production

1937

Number Produced:

5,033

Price:

1,150 RM

Engine


Internal Designation

M 69 S 5

Motor Type

Four Stroke single cylinder vertical

Bore x Stroke

84 x 78 mm (3.30 x 3.07 in)

Displacement

398 cc

Maximum Power

14hp at 4,000 rpm

Compression Ratio

5.7 : 1

Valves

OHV

Carburation System

1 x carburettor type SUM CK 3/500 Fr

Engine Lubricating System

Forced Feed Lubrication

Oil Pump

Gear Pump



Power Transmission


Clutch

Single plate dry clutch

Number of Gears

Four

Gear Shift

Manual tank shift gate

Gearbox Ratios

3.6 / 2.18 / 1.35 / 1.1

Rear Wheel Ratio

1 : 5.11 (1 : 5.63 with sidecar)

Bevel / Crownwheel

9 / 46 teeth (8 / 45 with sidecar)



Electrical System


Ignition System

Battery ignition

Generator

Bosch 6V/45W

Spark Plugs

Bosch DM 175/1







Chassis


Designation

F 69 S 5

Frame

Pressed steel duplex frame

Front Suspension

Plate spring, 9 laminae with 2 friction shock absorbers

Rear Suspension

Rigid

Wheel Rims

26 x 3.5

Front Tyre

26 x 3.5 SS

Rear Tyre

26 x 3.5 SS

Front Brakes

Drum brake 180 mm / 7.08 in diameter

Rear Brake

Drum brake 180 mm / 7.08 in diameter




Dimensions/Weights


Length x Width x Height

1980 x 850 x 950 mm (77.95 x 33.46 x 37.40 in)

Wheel Base

1300 mm / 5.11 in

Fuel Tank Capacity

12 litres / 2.63 gal / 3.17 gal US

Unladen Weight with full tank

137 kg / 301 lb

Permitted Weight Limit

200 kg / 440 lb

Fuel Consumption

3.5 litres per 100 kilometres approx / 80 mpg / 67 mpg US

Oil Consumption

1 - 2 litres per 1,000 kilometres

Top Speed

100  kph / 62 mph