BMW R90S 1973-1976 |
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| Engine | |||
| Configuration | Horizontally opposed air-cooled twin, pushrod operated valves, 2 per cylinder | 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) |
| 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 |
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R90S Specifications were the same throughout the model run
The cockpit remained basically unchanged throughout the R90S model run. The fairing was made of a composite resembling carbon fibre, as were the sidecovers.
Initially, switches were of the pushbutton variety, similar to those used on the stroke five models. Later renditions of the R90S had more modern switchblocks.
