Information kindly supplied by P.Hawksley

www.bmbikes.co.uk

 

 

 

 



Start of Production

1935

Click to View Available Literature

End of Production

1942

Number Produced:

36,000 (single and twin carb versions)

Price:

1,630 RM

Engine

 

Internal Designation

M 56 S 6 or 212

Motor Type

Four Stroke two cylinder flat twin

Bore x Stroke

78 x 78 mm (3.07 x 3.07 in)

Displacement

745 cc

Maximum Power

20hp at 4,000 rpm

Compression Ratio

5.2 : 1

Valves

SV

Carburation System

2 x Amal 6/406/407

Engine Lubricating System

Forced Feed Lubrication

Oil Pump

Gear Pump



Power Transmission

 

Clutch

Double plate dry clutch

Number of Gears

4

Gear Shift

Manual

Gearbox Ratios

3.18 / 2.06 / 1.42 / 1.09

Rear Wheel Ratio

1 : 4.07 (1 : 4.75 with sidecar)

Bevel / Crownwheel

14 / 57 teeth (12 / 57 with sidecar)



Electrical System

 

Ignition System

Magneto or battery ignition

Generator

Bosch D 245 RS 108

Spark Plugs

Bosch M 175 T1 or Bosch W 175 T1






Chassis

 

Designation

F66

Frame

Pressed steel twin loop frame

Front Suspension

Telescopic fork

Rear Suspension

Rigid

Wheel Rims

3 x 19

Front Tyre

3.5 x 19

Rear Tyre

3.5 x 19

Front Brakes

Drum brake 200 mm / 7.87 in diameter

Rear Brake

Drum brake 200 mm / 7.87 in diameter


Dimensions/Weights

 

Length x Width x Height

2100 x 900 x 940 mm (82.67 x 35.43 x 37.00 in)

Wheel Base

1380 mm / 54.33 in

Fuel Tank Capacity

14 litres / 3.07 gal / 3.69 gal US

Unladen Weight with full tank

185 kg approx / 407 lb

Permitted Weight Limit

300 kg / 660 lb

Fuel Consumption

4 - 4.5 litres per 100 kilometres approx / 70 - 62 mpg / 58 - 52 mpg US

Oil Consumption

1 - 2 litres per 1,000 kilometres

Top Speed

120  kph / 74 mph