R 90 S 1975
Engine
Configuration Horizontally opposed air-cooled twin, pushrod operated valves, 2 per cylinder [image] Lubrication Gear driven pump
Bore & Stroke 90 x 70.6 mm Ignition Kettering
Capacity 898 cc Charging system 12v  280w alternator
Compression Ratio 9.5 : 1 Starter Electric starter 0.5 hp
Maximum Power 67 DIN hp at 7000 rpm Transmission Gear driven primary drive, 3.00:1 bevel final drive (optional 2.91:1)
Diff and driveshaft
Maximum Torque 55 ft/lb (7.6 mkg) at 5500 rpm Gearbox 1st 4.40: 1 
2nd 2.86:1 
3rd 2.07:1 
4th 1.67:1 
5th 1.50:1
Fuel Dell'Orto PHM 38mm slide type carburettors 
Micronic air filter
Clutch Cable operated single plate dry clutch
Chassis
Frame Steel main and bolt-on subframe Wheels 1.85 x 19 front 
2.15 x 18 rear 
Spoked alloy rims
Dimensions  Weight: 215 kg wet 
Wheelbase: 1465 mm 
Length: 2180 mm 
Seat Height: 820 mm
Tyres 3.25 H 19 front 
4.00 H 18 rear 
Front Suspension Hydraulic telescopic  Brakes Front: 260 mm stainless undrilled discs with floating single piston calipers 
Rear: 200 x 30 mm drum
Rear suspension Boge dual dampers, springs adjustable for pre-load  Fuel Capacity 24 Litres (5 1/4 Imperial gallons)
including 2.5l reserve
Performance
Top Speed Upright: 195 kph (121 mph) 
Prone: 200 kph+ (125 mph+)
Fuel Economy 55.7 mpg (Imp.) at 68 mph
Acceleration Standing 400m: 13.3 sec 
Standing 1000m: 25.3 sec 
0-62.5 mph: 4.8 sec 
R90S - click for larger image
The BMW R90S
An all time classic
 

Click here for an image of a later model in Daytona colours (63k)
Images of the 1973 R90S

 
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