| MODEL | BMW R 100S 1978 |
| Year | 1978 |
| Engine Type | Four stroke, two cylinder horizontally opposed Boxer, 2 valves per cylinder |
| Displacement / Capacity | 980 cc / 59.8 cu in |
| Bore X Stroke | 94 x 70.6 mm |
| Compression Ratio | 9.5:1 |
| Cooling System | Air cooled |
| Max Power | 51 kW / 70 hp @ 7250 rpm |
| Max Torque | 76 Nm / 7.7 kgf-m / 56 lb-ft @ 6000 rpm |
| Ignition | Battery ignition |
| Induction | 2 x Bing 94/40/105 - 94/40/106 constant depression carburettors |
| Start System | Electric |
| TRANSMISSION SPECS | |
| Lubrication | Wet sump |
| Gear Box | 5 Speed |
| Clutch | Dry single plate, with diaphragm spring |
| Final Drive | Shaft |
| CHASSIS SPECS | |
| Frame | Double down tubes, dual cradle |
| Front Suspension | Telescopic fork with hydraulic shock absorber, 200 mm / 7.8 in travel |
| Rear Suspension | Long swinging arm with adjustable struts, 125 mm / 4.9 in travel |
| Front Brakes | 2 x 260 mm discs, 2 piston calipers |
| Rear Brakes | Drum |
| DIMENSION SPECS | |
| Overall Length | 2130 mm / 83.8 in |
| Overall Width | 746 mm / 29.37 in |
| Overall Height | 1210 mm / 47.6 in |
| Seat Height | 820 mm / 32.3 in |
| Wheelbase | 1465 mm / 57.67 in |
| Ground Clearance | 165 mm / 6.49 in |
| Dry Weight | — |
| Wet Weight | 220 kg / 484 lbs |
| WHEEL SPECS | |
| Front Tyre | 3.25-19 |
| Rear Tyre | 4.00-18 |
| FUEL SYSTEM | |
| Fuel Capacity | 24 Litres / 6.3 US gal |
| Fuel Consumption | 5.2 L/100 km / 19.1 km/l / 45 US mpg |
| Top Speed | 200 km/h / 124 mph |
Photo: K1200RSRIDER, CC BY-SA 4.0, via Wikimedia Commons
Photo: photobeppus, CC BY-SA 2.0, via Wikimedia Commons
For 1978 the R 100 S was given the full 70 hp tune of the RS, ending its deliberate power handicap. Apart from the extra output it stayed the same half-faired 980 cc sports twin, and around this time BMW began moving the sporting models over to cast "snowflake" wheels. It remained the sportier, lighter alternative to the fully faired RS.
