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1985 BMW R 100RS Overview
The 1985 BMW R 100RS is a classic motorcycle built around 980 cc of displacement. Under the tank sits a Four stroke, two cylinder horizontally opposed Boxer, 2 valves per cylinder engine, a compression ratio of 9.5:1. 1985 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 196 km/h, making it a capable performer in its class. From a practical standpoint, the 1985 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. That's roughly 35.9 kg heavier than the average classic motorcycle in our database. Scroll down for the complete 1985 BMW R 100RS spec sheet covering every technical detail from suspension travel to tyre sizes.
1985 R 100RS - Pros & Cons
Strengths
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Strong power output: 1985 BMW R 100RS makes 51 kW @ 7000 rpm with 76 Nm @ 6000 rpm of torque - competitive figures for its class.
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Large fuel range: The 24-litre tank is generously sized, translating to extended range between stops - ideal for touring or longer commutes.
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Low-maintenance final drive: Shaft final drive means no chain to clean, lube or adjust - meaningfully less routine maintenance than a chain-driven equivalent.
Considerations
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Carburetor fuelling: Carbureted engines need occasional jetting attention and can be reluctant in cold weather or at altitude compared to modern fuel-injected alternatives.
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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.
Wear Points & Servicing Notes
Heat management in traffic
R 100RS's air-cooled design means engine-bay temperatures build up more in stop-start traffic than on a liquid-cooled equivalent - a function of the cooling method itself, not a defect. Mesh riding gear and avoiding prolonged idling help in hot climates.
Carburetor maintenance
The R 100RS uses carburetion rather than fuel injection, which means jetting is altitude- and temperature-sensitive and benefits from a clean-and-rejet after extended storage or an exhaust change.
Brake disc and pad wear
The 2 x ∅260mm discs, 2 piston calipers front brake gives strong, progressive stopping power. Disc thickness and pad depth are worth checking at every tyre change, since worn pads can score the disc surface.
Suspension condition on used examples
Up front, the R 100RS runs Telescopic fork with hydraulic shock absorber and Long swinging arm with adjustable strut at the rear. On a used example, check fork seals for weeping oil and test the rear linkage for play - seals are a relatively cheap fix but useful when negotiating price.
Final drive maintenance
Final drive is by shaft - no chain or belt maintenance at all, though the drive-shaft oil should be changed on the manufacturer's interval.
Frame & chassis check
The frame is Double sown tubs, dual cradle - worth a visual check for corrosion or impact damage around the head-stock and swingarm pivot on any used example, since frame damage is far costlier to fix than any service item.
Handling the weight at a standstill
At 230 kg, the R 100RS is a substantial machine - low-speed manoeuvring in car parks takes more physical effort than on a lighter bike, though the weight disappears once rolling.
R 100RS - Buying & Maintenance Guide
What to check before buying
When inspecting a used 1985 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.
Carburetor upkeep
Keep the carburetors clean and free of deposits. If the R 100RS has been stored, strip and clean the carb float bowls before attempting to start it. Pilot jets are the first to block and the last to be checked - always include them in any carb rebuild.
1985 BMW R 100RS - Frequently Asked Questions
What engine does the 1985 BMW R 100RS have?
The 1985 BMW R 100RS uses a Four stroke, two cylinder horizontally opposed Boxer, 2 valves per cylinder engine with 980 cc of displacement. It is air cooled.
What is the top speed of the 1985 BMW R 100RS?
The 1985 BMW R 100RS has a factory-quoted top speed of 196 km/h. Real-world speeds vary depending on rider weight, conditions and state of tune.
How much does the 1985 BMW R 100RS weigh?
The 1985 BMW R 100RS weighs 230 kg. This is the manufacturer's wet figure.
How much power does the 1985 BMW R 100RS make?
The 1985 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 1985 BMW R 100RS?
The 1985 BMW R 100RS has a 24-litre fuel tank. At around 5-6 litres per 100 km, that is roughly 400-480 km between stops.
Is the 1985 BMW R 100RS suitable for shorter riders?
The 1985 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 1985 BMW R 100RS have?
The 1985 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 1985 BMW R 100RS use?
The 1985 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 1985 BMW R 100RS have?
The 1985 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. |
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- |
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
Four stroke, two cylinder horizontally opposed Boxer, 2 valves per cylinder
Power
51 kW / 70 hp / @ 7000 rpm
Torque
76 Nm / 7.75 kgf-m / 56 ft-lb @ 6000 rpm
Top Speed
196 km/h / 121.5 mph
Fuel Capacity
24 Litres / 6.3 US gal
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Full 1985 BMW R 100RS Specifications
Year
1984 - 85
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 Litres / 6.3 US gal
Wet Weight
230 kg / 506 lbs
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
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
Clutch
Dry single plate, with diaphragm spring
Final Drive
Shaft
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
Gear Ratios
1st 4.40 / 2nd 2.86 / 3rd 2.07 / 4th 1.67 / 5th 1.50:1
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 - Rear
Simplex ∅200 mm drum
Tyres - Front
3.25 - H19
Tyres - Rear
4.00 - H18
Wheel Ratio - Rear
1:2.91 or 1:3.00
Wheels - Front
2.15 - B19
Wheels - Rear
2.50 - B18
Specifications are compiled from manufacturer documentation and cross-referenced
technical sources, and corrected on an ongoing basis.
Spot an error? Let us know.
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