BMW GS Series – a Brief History

The GS has been available with a range of different engines including single cylinder, twin cylinder water-cooled and twin cylinder air (“Airheads”) and air/oil cooled (“Oilheads” and “Hexheads”).

The first shaft driven GS model was the R 80 G/S with a 797.5 cc air-cooled, flat-twin boxer engine. The BMW 247 engine, which was also fitted to many other bikes in the BMW range, is known as an airhead. The most valued version was the R 80 G/S-PD “Paris-Dakar” model featuring a larger tank. In certain markets a 649.6 cc R 65 GS version was also available. These early machines used a combined rear suspension and drive swingarm called a Monolever.

In 1987 the G/S name was changed to GS with the S meaning “Sport” rather than “Straße” and the Monolever was replaced with the Paralever swingarm, which included a torque arm intended to lessen shaft effect and strengthen the swingarm-to-final drive connection. The new bikes were produced with engines of 797.5 cc (R 80 GS) or 980 cc (R 100 GS).

Production of the standard machines stopped in 1995 with the R 100 GS-PD (unofficially Paris Dakar), but special “Kalahari” and “Basic” editions were made available in 1996 and 1997, which ended airhead GS production.

Airhead models still have a following among adventure motorcyclists.

Airhead production history

• Monolever
  • R 80 G/S 1980–1986
  • R 80 G/S-PD 1984–1987
  • R 65 GS 1987–1990
• Paralever
  • R 80 GS 1987–1994
  • R 100 GS 1987–1994
  • R 100 GS-PD 1988–1995
  • R 80 GS Basic 1996–1997
  • R 80 GS Kalahari 1996–1997

In 1995, the introduction of the next generation R-259 or oilhead engine signalled BMW’s entry into modern adventure models, with a succession of larger displacement models including the R 850 GS, R 1100 GS, R 1150 GS and the R 1200 GS. Later models have electronic engine management, ABS braking, twin spark plugs, and more power than airhead models. The current R 1200 GS, sometimes referred to as a hexhead because of the revised cylinder head shape, is 30 kg (66 lb) lighter and, with 105 horsepower (78 kW), more powerful than the R 1150 GS. Electronic fuel injection systems provided more even overall riding performance for the great range of altitudes commonly ridden with these motorcycles.

The R 1150 GS and R 1200 GS are available in an Adventure version which adds a larger fuel tank, lower gearing, upgraded suspension, and optional offroad tires to make the Adventure more suitable for arduous off-road trips with a heavy load of gear and supplies. The horizontally-opposed two-cylinder “boxer” engine provides a comparatively low centre of gravity compared to motorcycles with inline-4 or V-twin engines. This strongly contributes to the ability of these supra-liter class machines to travel on dirt roads and trails. The distribution of torque over a broad RPM range coupled with the relatively wide power pulses inherent in a long-stroke two cylinder motor provides consistent and predictable traction on loose surfaces.

As with the airheads, all oilhead GS models are shaft driven. The front suspension, however, was changed from conventional forks to the Telelever, developed by British company Saxon Motodd, which uses a control arm, called an A-arm by BMW to eliminate dive under braking.

Oilhead production history

From the start of oilhead production in 1994 until 27 July 2007, a total of 219,468 oilhead GS bikes were produced.^[2] Oilhead GS models are listed below together with production figures where known:

Model	Dates	Production
R 1100 GS	1994–1999	39,842
R 850 GS	1996–2001	2,242
R 1150 GS	1999–2004	58,023
R 1150 GS Adventure	2001–2005	17,828
R 1200 GS	2004–present	84,373 up to 27 July 2007
R 1200 GS Adventure	2006–present	15,627 up to 27 July 2007

Although not strictly a GS, the following closely related models were also introduced by BMW:

• HP2 Enduro 2005 – present date
• HP2 Megamoto 2007 – present date

Single cylinder chain drive

BMW introduced the fuel injected F 650 GS in 2000 following BMW’s win in the 1999 Dakar Rally with a heavily modified F 650 RR ridden by Richard Sainct. A taller, more off-road biased Dakar version was introduced which included a taller screen, 21 inch front wheel and longer suspension travel. BMW re-branded the single cylinder bike as the G650GS in some markets following the launch of the parallel twin-cylinder models in 2008.

The single cylinder bikes have a strong following and are thought by many of their riders to be better off roaders than the heavier boxer engined bikes. Like the larger two-cylinder models, they offer significant capacity to carry gear and supplies over long distances. Their versatility is attractive to riders who intend to spend weeks, months, even years travelling on two wheels.

The F 800 GS produces a power output of 63 kW (84 hp) and torque of 81 N·m (60 lb·ft) allowing it to achieve a 0-60 mph time of 4.1 seconds^{[citation needed]}. It has twin 300 mm discs at the front with optional ABS. It has a seat height of 880 mm (34.6 in).

Though it is made with the same engine as the F 800 GS, the F 650 GS produces a lower power output of 52 kW (70 hp) and torque of 75 N·m (55 lb·ft). This detuned engine can be further restricted to 25 kW (34 hp) to satisfy European regulations involving restricted licenses for young or new riders. It has a single 300 mm disc at the front with optional ABS. It has a lower seat height of 820 mm (32.3 in).

Both models feature chain drive, but the other F-series motorcycles now use a reinforced kevlar belt drive which requires less maintenance.