BMW R90S (1973-76 )

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The BMW R 90S was produced between 1973 and 1976, with a total of 17,465 units built. It features a four-stroke, two-cylinder horizontally opposed boxer engine with pushrod-operated two valves per cylinder, 898 cc capacity, and a compression ratio of 9.5:1. It is air-cooled and has a gear-driven pump for lubrication. The bike has a maximum power of 48.8 kW (67 hp) at 7000 rpm and a maximum torque of 76 Nm (55 ft-lb) at 5500 rpm. The clutch is a dry single plate with diaphragm spring, and it is equipped with a five-speed transmission and a shaft final drive. The front suspension is a telescopic fork with hydraulic shock absorber, while the rear suspension is a long swinging arm with an adjustable strut. The front brakes consist of two 260mm discs with a one-piston caliper, while the rear brake is a 200mm drum. The bike has 1.85 – B19 front wheel and a 2.15 – B18 rear wheel with dimensions of 2180 mm x 740 mm x 1210 mm (L x W x H) and a wheelbase of 1465 mm. It has a seat height of 820 mm and weighs 215 kg (473 lbs) with a 24-liter (6.3 US gal) fuel capacity. The bike has an average fuel consumption of 5.1 L/100 km (46 mpg) and a top speed of 200 km/h (124 mph). It is well-reviewed by Motorcycle-USA and Top Speed, with standing 1/4-mile times of 13.3 sec at 163 km/h (101 mph).

Technical specifications:

Make Model: BMW R 90S

Year: 1973-76


Production: 17465 units
Engine: Four stroke, two cylinder horizontally opposed Boxer, pushrod operated 2 valves per cylinder.
Capacity: 898 cc / 54.8 cu in.
Bore x Stroke: 90 x 70.6 mm
Cooling System: Air cooled
Compression Ratio: 9.5:1
Lubrication: Gear driven pump
Induction: 2 x slide Dell’Orto PHM 38 carburetors
Ignition: Kettering
Charging System: 12V 280W alternator
Starting: Electric
Clutch: Dry single plate, with diaphragm spring
Max Power: 48.8 kW / 67 hp @ 7000 rpm
Max Torque: 76 Nm / 7.6 kgf-m / 55 ft-lb @ 5500 rpm
Clutch: Dry single plate, with diaphragm spring

Transmission: 5 Speed
Final Drive: Shaft
Gear Ratios: 1st 4.40 / 2nd 2.86 / 3rd 2.07 / 4th 1.67:1 / 5th 1.50:1
Frame: Double-loop tubular frame with bolt-on rear section
Front Suspension: Telescopic fork with hydraulic shock absorber
Front Wheel Travel: 208 mm / 8.1 in
Rear Suspension: Long swinging arm with adjustable strut.
Rear Wheel Travel: 125 mm / 4.9 in
Front Brakes: 2 x 260mm discs, 1 piston caliper
Rear Brakes: 200mm Drum
Front Wheel: 1.85 – B19
Rear Wheel: 2.15 – B18
Front Tyre: 3.25 – H19
Rear Tyre: 4.00 – H18
Dimensions: Length 2180 mm / 85.82 in Width 740 mm / 29.13 in Height 1210 mm / 47.63 in
Wheelbase: 1465 mm / 57.67 in
Seat Height: 820 mm / 32.2 in
Ground Clearance: 165 mm / 6.49 in
Wet Weight: 215 Kg / 473 lbs
Fuel Capacity: 24 Litres / 6.3 US gal

Consumption Average: 5.1 L/100 km / 19.6 km/l / 46 mpg
Standing 1/4 Mile: 13.3 sec / 163 km/h / 101 mph
Top Speed: 200 km/h / 124 mph
Reviews: Motorcycle-USA / Top Speed

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