R75/5

Start of Production

1969

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End of Production

1973

Numbers Produced

38,370

Price

4,996 DM

Engine

Motor Type

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

Bore x Stroke

82 x 70.6 mm (3.22 x 2.77 in)

Displacement

745 cc

Max Power

50 hp (36.8 KW) at 6,200 rpm

Max Torque

60 Nm / 44 ft lb at 5,000 rpm

Compression Ratio

9.0 : 1

Valves Per Cylinder

2

Valve Control

OHV, using push rod and rocker arm

Carburation System

2 constant depression carburettors, Bing 64/32/4-3 or 64/32/9-10

Engine Lubricating System

Wet sump

Power Transmission

Clutch

Dry single plate, with diaphragm spring

Number of Gears

4

Gear Selection

Dog type gearbox (ratchet foot lever)

Gearbox Ratios

3.896 / 2.578 / 1.875 / 1.50 :1

Rear Wheel Ratio

1 : 3.2 (1 : 2.91 optional) Some European Police Forces used the higher gearing (Thanks to Rob James for this information)

Bevel/Crownwheel

10 / 32 teeth (11 / 32 optional) The rear bevel on the very early production models was 32/11 or 2.91 to 1.  Authorities using this model found the gearing high for certain applications and I believe overtures were made to BMW to lower the rear bevel ratio.  In any event the 75/5 soon appeared with the 32/10 drive and many owners switched out the high ratio for it.  I come across the odd 70 model still using the high gear bevel now and then; even in the US with our endless, tedious Interstates, the gear appears too high for the 750 to pull with ease. Thanks to Rob James for this info.

Electrical System

Ignition System

Battery ignition

Alternator

Bosch 12 V/180 W

Starter

Bosch 0.5 hp

Spark Plugs

Bosch W 200 T 30 / Beru 200/14/3 A / Champion N7Y

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 strut

Spring Travel Front/Rear

208 / 125 mm (8.18 x 4.92 in)

Wheel Rims, Front

1.85 B 19

Wheel Rims, Rear

1.85 B 18 or 2.15 B 18

Tyres, Front

3.25 S 19

Tyres, Rear

4.00 S 18

Brakes, Front

Duplex drum brake 200 mm / 7.87 in diameter

Brakes, Rear

Simplex drum brake 200 mm / 7.87 in diameter

Dimensions / Weights

Length x Width x Height

2100 (from 1973: 2150) x 852 x 1040 mm (82.67 (84.64) x 33.54 x 40.94 in)

Wheel Base

1385 mm / 54.52 in (from 1973: 1435 mm / 56.49 in)

Fuel Tank Capacity

24 litres / 5.27 gal / 6.34 gal US (from 1971: 17 litres / 3.73 gal / 4.49 gal US)

Unladen Weight with Full Tank

210 Kg / 462 lb (from 1971: 205 Kg / 451 lb)

Max. Permissible Weight

398 Kg / 876 lb

Ground Clearance

165 mm / 6.49 in

Seat Height (Unladen)

850 mm (33.5 inches)

Fuel Consumption

4.5 litres 100Km (at constant 90 Kph) / 62 mpg / 52 mpg US

Top Speed

175 Kph / 108 mph

Acceleration 0 - 100 Kph / 62 mph

6.4 seconds