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 |
