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1981 BMW R 100RS Overview
The 1981 BMW R 100RS is a classic motorcycle built around 980 cc of displacement. Under the tank sits a Two cylinder boxer engine running OHV valve actuation, a compression ratio of 9.5:1. The bore and stroke measures 94 x 70.6 mm. 1981 BMW R 100RS delivers 51 kW @ 7000 rpm of peak power and 76 Nm @ 6000 rpm of torque. The factory-quoted top speed stands at 193 km/h, making it a capable performer in its class. From a practical standpoint, the 1981 R 100RS tips the scales at 230 kg, carries a 24-litre fuel tank, offers a seat height of 820 mm and spans a 1465 mm wheelbase. Scroll down for the complete 1981 BMW R 100RS spec sheet covering every technical detail from suspension travel to tyre sizes.
1981 R 100RS - Pros & Cons
Strengths
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⚡
Strong power output: 1981 BMW R 100RS makes 51 kW @ 7000 rpm with 76 Nm @ 6000 rpm of torque - competitive figures for its class.
Considerations
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📏
Tall seat height: The 820 mm seat height will challenge shorter riders - tiptoeing at low speeds is something to factor into your decision.
Owner Experiences & Common Issues
Low-speed confidence
At 230 kg, the R 100RS is a substantial machine. New owners occasionally mention that slow-speed manoeuvring in car parks takes a little getting used to. Once moving, the weight disappears - but practising slow-speed exercises builds confidence quickly.
R 100RS - Buying & Maintenance Guide
What to check before buying
When inspecting a used 1981 BMW R 100RS, start with the basics: check the service book for oil change frequency, inspect the chain and sprockets for wear, and look for oil seepage around the engine casings and rocker covers. A cold start test is invaluable - a well-maintained R 100RS should fire up cleanly and settle to a smooth idle within a few seconds.
Oil and filter changes
Regular oil changes are the single most important maintenance task on any R 100RS. Stick to the manufacturer's interval - typically every 6,000 km or once a year, whichever comes first. Always use the correct viscosity grade as specified in the owner's manual.
1981 BMW R 100RS - Frequently Asked Questions
What engine does the 1981 BMW R 100RS have?
The 1981 BMW R 100RS uses a Two cylinder boxer engine with 980 cc of displacement. It is air cooled.
What is the top speed of the 1981 BMW R 100RS?
The 1981 BMW R 100RS has a factory-quoted top speed of 193 km/h. Real-world speeds vary depending on rider weight, conditions and state of tune.
How much does the 1981 BMW R 100RS weigh?
The 1981 BMW R 100RS weighs 230 kg. This is the manufacturer's wet figure.
How much power does the 1981 BMW R 100RS make?
The 1981 BMW R 100RS produces 51 kW @ 7000 rpm of power and 76 Nm @ 6000 rpm of torque. These are peak figures.
What is the fuel tank capacity of the 1981 BMW R 100RS?
The 1981 BMW R 100RS has a 24-litre fuel tank.
Is the 1981 BMW R 100RS suitable for shorter riders?
The 1981 BMW R 100RS has a seat height of 820 mm. This is towards the tall end of the spectrum and will require most riders under 175 cm to tiptoe at stops.
What brakes does the 1981 BMW R 100RS have?
The 1981 BMW R 100RS uses 2 x ∅260mm discs, 2 piston calipers at the front and Simplex ∅200 mm drum at the rear.
What tyre sizes does the 1981 BMW R 100RS use?
The 1981 BMW R 100RS runs 3.25 - H19 front and 4 - H18 rear tyres. A good selection of sport, touring and all-weather rubber is available in these sizes.
What gearbox does the 1981 BMW R 100RS have?
The 1981 BMW R 100RS is fitted with a 5 Speed transmission.
BMW R 100RS Spec Evolution
The BMW R 100RS was produced across 9 model years (1976-1989). The table below highlights the key specifications that changed across the production run - useful whether you are comparing years or tracking down a specific variant.
| Specification |
1976 |
1977 |
1979 |
1981 |
1983 |
1985 |
1987 |
1988 |
1989 |
| Max Power |
51 kW / 70 hp / @ 7000 rpm |
51 kW / 70 hp / @ 7000 rpm |
51 kW / 70 hp / @ 7000 rpm |
51 kW / 70 hp / @ 7000 rpm |
51 kW / 70 hp / @ 7000 rpm |
51 kW / 70 hp / @ 7000 rpm |
- |
- |
43.8 kW / 59.5 hp @ 6500 rpm |
| Wet Weight |
230 kg / 506 lbs |
230 kg / 506 lbs |
230 kg / 506 lbs |
230 kg / 506 lbs |
247.0 kg / 544.5 lbs |
230 kg / 506 lbs |
243.0 kg / 535.7 lbs |
243.0 kg / 535.7 lbs |
243.0 kg / 535.7 lbs |
| Engine Type |
- |
- |
- |
Two cylinder boxer, four-stroke |
Two cylinder boxer |
- |
Two cylinder boxer |
Two cylinder boxer |
Two cylinder boxer |
| Top Speed |
196 km/h / 121.5 mph |
196 km/h / 121.5 mph |
196 km/h / 121.5 mph |
196 km/h / 121.5 mph |
193.0 km/h / 119.9 mph |
196 km/h / 121.5 mph |
186.0 km/h / 115.6 mph |
186.0 km/h / 115.6 mph |
186.0 km/h / 115.6 mph |
| Fuel Capacity |
24 Litres / 6.3 US gal |
24 Litres / 6.3 US gal |
24 Litres / 6.3 US gal |
24 Litres / 6.3 US gal |
24 Litres / 6.3 US gal |
24 Litres / 6.3 US gal |
22.00 litres / 5.81 gallons |
22.00 litres / 5.81 gallons |
22.00 litres / 5.81 gallons |
| Displacement |
980 cc / 59.8 cub in. |
980 cc / 59.8 cub in. |
980 cc / 59.8 cub in. |
980 cc / 59.8 cub in. |
980 cc / 59.8 cub in. |
980 cc / 59.8 cub in. |
- |
- |
980 cc / 59.8 cu in |
| Brakes - Front |
2 x ∅260mm discs, 2 piston calipers |
2 x ∅260mm discs, 2 piston calipers |
2 x ∅260mm discs, 2 piston calipers |
Dual disc |
Dual disc |
2 x ∅260mm discs, 2 piston calipers |
Dual disc |
Dual disc |
2 x ∅285mm discs, 2 piston calipers |
| Wheelbase |
1465 mm / 57.67 in |
1465 mm / 57.67 in |
1465 mm / 57.67 in |
1465 mm / 57.67 in |
1465 mm / 57.67 in |
1465 mm / 57.67 in |
- |
- |
1447 mm / 57.67 in |
Key Specifications
Engine
Two cylinder boxer
Power
51 kW / 70 hp / @ 7000 rpm
Torque
76 Nm / 7.75 kgf-m / 56 ft-lb @ 6000 rpm
Top Speed
193.0 km/h / 119.9 mph
Fuel Capacity
24.00 litres / 6.34 gallons
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Full 1981 BMW R 100RS Specifications
Year
1980 - 81
Make Model
BMW R 100RS
Seat Height
820 mm / 32.3 in
Wheelbase
1465 mm / 57.67 in
Ground Clearance
165 mm / 6.49 in
Height
1300 mm / 51.8 in
Length
2130 mm / 83.8 in
Width
746 mm / 29.37 in
Fuel Capacity
24.00 litres / 6.34 gallons
Fuel Capacity
24 Litres / 6.3 US gal
Wet Weight
247.0 kg / 544.5 lbs
Wet Weight
230 kg / 506 lbs
Stroke
4
Fuel Control
OHV
Engine Type
Two cylinder boxer
Displacement (ci)
59.74 cubic inches
Displacement (cc)
979.00 cc
Bore x Stroke (mm)
94.0 x 70.6 mm
Bore x Stroke (in,)
3.7 x 2.8 inches
Fuel Control
OHV
Engine Type
Two cylinder boxer, four-stroke
Displacement
980 cc / 59.8 cub in.
Engine Detail
Four stroke, two cylinder horizontally opposed Boxer, 2 valves per cylinder
Bore x Stroke
94 x 70.6 mm
Compression Ratio
9.5:1
Compression Ratio
9.5:1
Cooling System
Air cooled
Fuel Consumption
4.8 L/100 km / 20.8 km/l / 49 US mpg
Fuel Induction
2 x Constant depression carburettors, Bing 94/40/105 - 94/40/106
Ignition
Battery ignition
Lubrication
Wet sump
Starter
Electric
Valve System
2
Valve System
2
Clutch
Dry single plate, with diaphragm spring
Final Drive
Shaft
Final Drive
Shaft drive (cardan)
Final Drive Gear Ratio (Bevel/Crown Teeth)
11/32 teeth or 10/32 teeth
Gear Ratios
1st 3.38 / 2nd 2.43 / 3rd 1.93 / 4th 1.67 / 5th 1.50
Gearbox
5-speed
Gearbox
5-speed
Transmission / Drive
5 Speed
Frame Type
Double sown tubs, dual cradle
Suspension - Front
Telescopic fork with hydraulic shock absorber.
Suspension - Rear
Long swinging arm with adjustable strut.
Wheel Travel - Front
200 mm / 7.8 in
Wheel Travel - Rear
125 mm / 4.9 in
Alternator
Bosch 12V/240 W
Brakes - Front
2 x ∅260mm discs, 2 piston calipers
Brakes - Front
Dual disc
Brakes - Rear
Simplex ∅200 mm drum
Brakes - Rear
Single disc
Tyres - Front
3.25 - H19
Tyres - Front
3.25-19
Tyres - Rear
4.00 - H18
Tyres - Rear
4.00-18
Wheel Ratio - Rear
1:2.91 or 1:3.00
Wheels - Front
2.15 - B19
Wheels - Rear
2.50 - B18
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