|Engine||797.5 cc (48.67 cu in) flat-twin boxer|
|Bore / stroke||84.8 mm × 70.6 mm (3.34 in × 2.78 in)|
|Top speed||104 mph (167 km/h)|
|Power||50 hp (37 kW)|
|Torque||41 lb·ft (56 N·m)|
|Transmission||5-speed shaft drive|
|Suspension||Front: Telescopic forks
Rear: Single spring / shock absorber
|Brakes||Front: Single 260 mm disc
Rear: 200 mm drum
|Wheelbase||1,465 mm (57.7 in)|
|Dimensions||L 2,230 mm (88 in)
W 820 mm (32 in)
H 1,150 mm (45 in)
|Seat height||860 mm (34 in)|
|Weight||186 kg (410 lb) (wet)|
|Fuel capacity||19.5 litres (4.3 imperial gallons)|
The BMW R80G/S is a motorcycle manufactured in Berlin, Germany, by BMW Motorrad from 1980 to 1987. Production totalled 21,864 bikes. It was the first in the BMW GS family of specialised dual-sport bikes, of which over 500,000 have been produced. The designation G/S is an acronym of the German words Gelände/Strasse, which mean offroad/road – highlighting the bike's dual sport design.
The R80G/S (G for Gelände "offroad" in German S for Strasse "street") was the first large displacement multisport bike on the market. The G/S was fitted with a 797.5 cc (48.67 cu in) BMW type 247 engine, which is a flat-twin (boxer) sometimes known as an airhead. The engine, which was fitted into an R65 frame, was a modified version of that fitted to the R80/7, featuring Nikasil cylinders, electronic ignition and a lighter flywheel. At the rear the bike had a new design combined single-sided swingarm and drive shaft – called a monolever with the rear dampening provided by a single shock absorber. The monolever was stiffer and lighter than the design fitted to previous models, and was subsequently fitted to other BMW motorcycles. It was a sealed suspension lever with the driveline inside the lever filled with oil to lubricate the shaft and parts. The single sided swing arm enabled the rear wheel to be removed easily with the bike on the center stand. It differs from other BMW road bikes of the same era due to its lighter weight, longer suspension travel, and large 21 inch front wheel. The bike gained popularity with adventure-seeking travellers after having won the Paris-Dakar ralley several times. BMW offered numerous optional parts including a 32-litre (7.0 imp gal; 8.5 US gal) fuel tank with Gaston Rahier's signature, a solo seat, stainless exhaust and a larger battery meaning that for the first time a true adventure travel motorcycle could be purchased directly from a manufacturer. The market it created spawned many aftermarket motorcycle accessories, such as larger fuel tanks and panniers.
R80G/S in motorsport
The R80G/S was developed for BMW by engineer Rüdiger Gutsche, a successful competitor in the International Six Days Trial on his specially adapted R75/5. In 1981, Hubert Auriol, riding a R80G/S prepared by German company HPN Motorradtechnik, won the Paris-Dakar Rally. He repeated his success on a 870 cc version of the R80G/S in 1983. Gaston Rahier won the Dakar on a R80G/S in 1984, and then again on a larger 1,000 cc engined R80G/S in 1985. To commemorate their success, BMW launched the R80G/S Paris-Dakar special edition which featured a 7 imperial gallons (32 l; 8.4 US gal) fuel tank, fitted with dual petcocks and signed by Gaston Rahier.
In 1986, the R80G/S was joined by the R100GS, which had a larger capacity 980 cc engine and an updated suspension and drive unit called a Paralever. In 1987, production of the R80G/S ended and was succeeded by the 650 cc R65GS, which used the same monolever suspension and drive, and the R80GS, which retained the G/S engine but used the newer Paralever drive.
- "500,000th GS comes off the production line". MCNEWS.com.au. 27 May 2009. Retrieved 28 May 2009.
- Falloon, The BMW Story, pp. 85
- Henshaw, Peter (2008). BMW GS. Veloce Publishing Ltd. pp. 13–14. ISBN 1-84584-135-2.
- Falloon, Ian (2009). The BMW Boxer Twins Bible: All Models 1970-1995. Veloce Publishing Ltd. p. 22. ISBN 1-84584-168-9.
- Falloon, The BMW Story, pp. 88
- Zimmerman, Mark; Nelson, Brian J. (2003). BMW Motorcycle Buyer's Guide. MotorBooks/MBI Publishing Company. p. 88. ISBN 0-7603-1164-1.
- Holmstrom, Darwin; Nelson, Brian J. (2002). BMW Motorcycles. MotorBooks/MBI Publishing Company. p. 129. ISBN 0-7603-1098-X.
- Falloon, The BMW Story, pp. 87