Start of Production

1978

Click to View Available Literature

End of Production

1985

Numbers Produced

29,454

Price

6,980 DM

Engine

 

Motor Type

Four-stroke two cylinder horizontally opposed "Boxer" engine, air cooled

Bore x Stroke

82 x 61.5 mm (3.22 x 2.42 in)

Displacement

649.6 cc

Max Power

45 hp (33 Kw) at 7,250 rpm. From 1981 50 hp 37 Kw at 7,250

Max Torque

50 Nm / 36 ft lb at 5,500 rpm. From 1981 model: 52.3 Nm / 38 ft lb at 6500 rpm

Compression Ratio

9.2 : 1

Valves Per Cylinder

2

Valve Control

OHV, using push rod and rocker arm

Carburation System

2 constant depression carburettors, Bing 64/32/2030 -  64/32/2040 or 64/32/307 - 64/32/308

Engine Lubricating System

Wet sump



Power Transmission

 

Clutch

Dry single plate, with diaphragm spring

Number of Gears

5

Gear Selection

Dog type gearbox (ratchet foot lever)

Gearbox Ratios

4.4 / 2.86 / 2.07 / 1.67 / 1.50 : 1

Rear Wheel Ratio

1: 3.44

Bevel/Crownwheel

9 / 31 teeth



Electrical System

 

Ignition System

Battery ignition. From 1981 model: Contact free electronic ignition

Alternator

Bosch 280 W

Starter

Bosch 0.7 hp

Spark Plugs

Bosch W 5 D / Beru 14-5D / Champion N 6 Y






Chassis

 

Type of Frame

Double loop tubular frame with bolt on rear section

Front wheel suspension

Telescopic fork with hydraulic shock absorber

Rear wheel suspension

Long swinging arm with adjustable strut

Spring Travel Front/Rear

175 / 110 mm (6.88 / 4.33 in)

Wheel Rims, Front

1.85 B 18

Wheel Rims, Rear

2.50 B 18

Tyres, Front

3.25 S 18

Tyres, Rear

4.00 S 18

Brakes, Front

Single disc brake 260 mm / 10.23 in diameter. Twin disc on later models. ATE 2 piston caliper to 1979. 1979 on models Brembo 2 piston caliper

Brakes, Rear

Simplex drum brake 200 mm / 7.87 in diameter




Dimensions/Weights

 

Length x Width x Height

2110 x 688 x 1090 mm (83.07 x 27.08 x 42.91 in)

Wheel Base

1390 mm / 54.72 in to 1980. 1400 mm / 55.11 in

Fuel Tank Capacity

22 litres / 4.83 gal / 5.81 gal US

Unladen Weight with Full Tank

205 Kg / 451 lb

Max. Permissible Weight

398 Kg / 876 lb

Ground Clearance

130 mm / 5.11 in

Seat Height (Unladen) Up to 1980

770 mm (30.3 inches)

Seat Height (Unladen) 1981 On

810 mm (31.9 inches)

Fuel Consumption

4.6 litres 100 Km (at constant 90 Kph) / 61 mpg / 51 mpg US

Top Speed

175 Kph / 108 mph

Acceleration 0 - 100 Kph / 62 mph

5.9 seconds (1981 model on: 5.8 seconds)

Information kindly supplied by P.Hawksley

www.bmbikes.co.uk