Information kindly supplied by P.Hawksley

www.bmbikes.co.uk

Start of Production

1937

Click to View Available Literature

End of Production

1937

Numbers Produced

1,850

Price

1,375 RM

Engine

 

Internal Designation

261

Motor Type

Four-stroke two cylinder flat twin

Bore x Stroke

70 x 78 mm2.75 x 3.07 in)

Displacement

600 cc

Max Power

18 hp at 4,500 rpm

Compression Ratio

6.0 : 1

Valves

SV

Carburation System

2 x carburettor type Amal M 75/426/S

Engine Lubricating System

Forced feed lubrication

Oil Pump

Gear pump



Power Transmission

 

Clutch

Single plate, dry

Number of Gears

4

Shifting

Foot shifting (+ auxiliary manual lever on the gear block)

Gearbox Ratios

3.6 / 2.28 / 1.7 / 1.3

Rear Wheel Ratio

1 : 3.89 (1 : 4.62 with sidecar)

Bevel/Crownwheel

9 / 35 teeth (8 / 37 with sidecar)



Electrical System

 

Ignition System

Battery ignition

Generator

Bosch RD 45/6 2800 RS 15

Spark Plugs

Bosch W 175 T1






Chassis

 

Designation

250

Frame

Twin loop pressed steel frame

Front wheel suspension

Telescopic fork

Rear wheel suspension

Rigid

Wheel rims

3 x 19

Tyres, Front

3.5 x 19

Tyres, Rear

3.5 x 19

Brakes, Front

Drum brake 200 mm / 7.87 in diameter

Brakes, Rear

Drum brake 200 mm / 7.87 in diameter




Dimensions/Weights

 

Length x Width x Height

2130 x 800 x 950 mm (83.85 x 31.49 x 37.40 in)

Wheel Base

1400 mm / 55.11 in

Fuel Tank Capacity

15 litres / 3.29 gal / 3.96 gal US

Unladen Weight with Full Tank

175 Kg / 3.85 lb

Load Rating

210 Kg / 462 lb

Fuel Consumption

Approx. 3.5 litres per 100 Km / 80 mpg / 67 mpg US

Oil Consumption

Approx. 1 litre per 1,000 Km

Top Speed

125 Kph / 77 mph