1973 BMW R90S
Engine
Engine type Four-stroke two cylinder horizontally opposed "Boxer" engine, air cooled
Bore x Stroke 90.0 x 70.6 mm (3.54 x 2.77 inches)
Displacement 898 cc
Valves 2 valves per cylinder; OHV, using push rod and rocker arm
Compression ratio 9.5:1
Max Power 67 hp (49.3 KW) @ 7000 rpm
Max Torque 76 Nm / 56 ft lb @ 5500 rpm
Fuel system 2 slide carburettors, Dellorto PHM 38 AS-AD or 38 BS-BD
Transmission 5-speed; Dog type gearbox (ratchet foot lever)
Final drive Cardan
Clutch Dry single plate, with lever action diaphragm spring
Ignition type Battery ignition
Starting system Electric starter
Lubrication Wet sump
Exhaust
Spark plug Bosch W 200 T 30 / Beru 200/14/3 A / Champion N7Y
Generator
Gear ratios 4.4 / 2.86 / 2.07 / 1.67 / 1.50
Dimensions
Frame type Double loop tubular frame with bolt on rear section
Castor
Overall length 2180 mm (85.82 inches)
Overall width 740 mm (29.13 inches)
Overall height 1210 mm (47.63 inches)
Wheelbase 1465 mm (57.67 inches)
Seat height 820 mm
Ground clearance 165 mm
Dry weight 215 kg
Fuel capacity 24 litres
Colors
Suspension (front) Telescopic fork with hydraulic shock absorber
Suspension (rear) Long swinging arm with adjustable strut
Tyre (front) 3.25 H 19
Tyre (rear) 4.00 H 18
Brake (front) Dual disc brake 260 mm / 10.23 in diameter. ATE 1 piston caliper
Brake (rear) Simplex drum brake 200 mm / 7.87 in diameter
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