BMW releases 800GS

BMW has launched its much-anticipated F 800GS locally.

The 800 parallel twin offers a lighter and more manageable alternative to the firm's class-leading 1200GS boxer and is set to shake up the middleweight adventure bike class.

It has been priced at $16,750 plus ORC, with switchable ABS costing an additional $1265.

Here is BMW's information kit:
The new BMW F800GS is set to continue the legend of the GS brand established by the Boxer-engined R 80 G/S and enhanced over many subsequent generations, along with the single-cylinder BMW F 650 GS models which secured impressive success at the highest level in adventure rallying.

In Australia, the R 1200 GS is BMW Motorrad's single biggest seller, and the F 650 GS single-cylinder predecessor was also one of the most popular models in the line-up. With that in mind it is not surprising that levels of anticipation have reached an all time high in the lead up to the arrival of the new F 800 GS.

Where some large-capacity adventure bikes sometimes reach their limits because of their weight or overall design, the new BMW F 800 GS will prove to be unstoppable.

The F 800 GS combines stability, high power and light weight, excellent ground clearance, long suspension travel, precise steering and sophisticated ergonomics; all of which delivers excellent off-road riding and excellent long-distance performance.

The chassis combines all the ingredients of a true adventure bike: a sturdy steel tube frame with a wide 42degrees of steering lock, rigid upside-down forks with 230 mm of travel, a sturdy aluminium double-strut swing arm with a path-dependent cushioned spring strut and 215mm of suspension travel, and solid wire-spoke wheels.

A 21-inch front wheel in the traditional 90/90-21 tyre size gives stability in slow off-road riding, and the 17-inch rear wheel is shod with a 150/70-17 tyre to ensure engine power is always transferred securely to the ground.

The engine is borrowed from the BMW F 800 S and modified for GS duties, with its cylinders now only inclined 8.3 degrees forward. The strong, liquid-cooled four-valve two-cylinder motor offers impressive, responsive performance with high torque and low fuel consumption.

The engine produces 63kW (85hp) at 7500rpm and 83 Nm of torque at 5750rpm.

The engine uses a unique balancer shaft to ensure smooth running. This comprises an additional swivelling con-rod that balances the first and second level mass forces to reduce vibration.

A low dry weight of 178 kg makes a major contribution to dynamic riding properties. When fuelled, and ready to ride, the BMW F 800 GS tips the scales at just 207 kg.

The F 800 GS offers an excellent level of seat comfort for both rider and pillion passenger, along with a high standard of safety features.

The two-channel switchable BMW ABS system is available as an option.

BMW F800GS Specification at a glance:

A young favourite at the heart of the new F 800 GS
The parallel twin engine used in the new BMW F 800 GS is very similar to that used in the successful F800S/ST models. The engine has been subtly modified to cope with the intended purpose of the new machine.

For excellent suspension travel and good weight distribution, the cylinders are now only angled forward by 8.3 degrees instead of the 30 degrees with the F800S/ST. This was made possible by a new design for the lower engine housing section made from die-cast aluminium which contains attachment points for the engine bash guard. Plus, the cylinder head has been reinforced where it attaches to the frame at the front.

A redesigned clutch cover allows easier manoeuvring when on the pegs, and creates room for a new oil dipstick and a different clutch release shaft.

Finally, the water pump housing and cooling hose connections have been adapted to the new position of the engine.

A bonus is that these modifications shave 1 kg off the engine's weight compared with that of the F 800 S/ST models.

The transverse parallel twin works with an even firing order (360°ignition offset) without crank offset on the crankshaft.

Because there is one firing cycle for each crankshaft rotation, the sound is deliberately like that of boxer engines which work with an identical firing offset. Most importantly, however, this configuration provides excellent power and torque characteristics for a mid size GS machine.

Unique mass balance
The mass forces of the piston and con rod are offset by a balancing mechanism that is unique in production engine design. Instead of having conventional counterweight shafts, the oscillating mass forces are balanced by a joint system on the centre of the crankshaft with specifically positioned counterweight masses: an eccentric on the crankshaft, offset against the crank pins by 180°, carries what is known as a balancing correcting rod. This connecting rod is hinged to an approximately horizontal balancing rocker.

The balancing connecting rod moves contrary to the two engine connecting rods. Because it is guided through the relatively long rocker, an almost linear swivel movement of the connecting rod head is achieved. In actual fact the small connecting rod eye describes a slightly curving path.

The mass distribution at the connecting rod head and rocker is chosen in such a way that the mass forces resulting from the swinging movement combat, in every crankshaft position, the oscillating mass forces from the crank drive (piston and con-rod proportion). This means that first and second order mass forces are almost completely eliminated, resulting in low-vibration engine running.

In order to prevent puncture losses, a semi-dry sump lubrication system has been designed which works without any separate engine oil tank. Lubricant flowing from the main bearings collects in a tray which also holds the balancing system and which is sealed off from the actual oil tray. Engine oil in this area is constantly vacuumed up by an oil pump and transported to the transmission housing, before running from there, under no pressure, via openings in the crank housing into the oil tray. The oil pressure pump supplies the lubricating oil system from this reservoir.

Camshafts matched to enduro requirements
The GS boasts a high tech cylinder head, derived from K Series technology. A pair of camshafts driven by a toothed chain, rotate and control four valves per cylinder via cam followers.

The F800GS uses slightly modified camshafts which help the engine develop its power in a way that is ideal for adventure machines: with excellent torque that is evenly delivered and easily controllable. The valve drive via cam followers is low-wear, only produces minimal friction losses and is particularly rev-proof. The valve play therefore only needs to be checked after 20,000 km.

Fuel injection uses BMS-KP engine control and two 46mm throttle valves. The injection quantity is determined by the specially tuned engine control, not only via the injection period but also via the pressure that the petrol pump provides, driven by the power requirement.

The fuel system operates without return and only carries the quantity that the engine actually needs. Because of this economical, patented regulation system, the fuel pressure can be modified within a wide range so that the mixture is always ideal. To measure the fuel quantity supplied, not only the well-known parameters such as load, engine speed and temperature are used, but also the residual oxygen content in the exhaust gas.

A lambda probe is positioned where the manifolds join. This is followed immediately by the three-way catalytic converter, which warms up quickly.

Intake air is fed by snorkels that poke out into the air stream, sited well above the engine, ideal for all types of riding environments. The openings are visible alongside the headlamp fairing.

High-revving with great torque
It is not only the modern injection system that ensures a prompt response from the F800GS twin; its low mass also contributes to its agile power development. Even at the bottom of its rev range, the four-valve engine, with a bore-stroke of 82 mm and 75.6 mm, is not short-stroked. Thus it is able to rev freely to release 90 percent of maximum torque in a broad range between 4,000 rpm and 7,500rpm.

Peak power of 63kW is achieved at 7,500rpm while 83Nm of peak torque arrives at just 5,750rpm.

In combination with the low total weight and closely stepped six-speed gearbox, the engine accelerates from 0-100km/h in about 4 seconds, and the top speed is in excess of 200km/h.

But it is not only the acceleration of the new GS model that is impressive; its traction is also remarkable. BMW development engineers have focussed quite deliberately on the smooth, confident development of power in the mid engine speed range rather than on absolute peak performance. Sporting riders will enjoy the engine's acceleration, while adventure riders will enjoy positive traction with minimal gear-shifting.

Low fuel use is a further strength with consumption of less than 5-litres (of Premium) per 100 km expected.

If necessary, the F800GS can be switched to run on regular unleaded (via CIP programming), with a marginal drop in output and a small increase in consumption.

The water pump is fitted on the right of the cylinder head and is gear driven by a cog wheel unit on the camshaft. As it is located directly behind the cooler with an integrated thermostat, only short hose connections are needed. The engine therefore looks compact and tidy.

An oil-water heat exchanger sited next to the easily accessible oil filter ensures that the engine warms up quickly after a cold start. In addition, the heat exchanger also limits the engine oil temperature.

A sturdy tubular steel frame
The tubular steel frame was designed especially for the new GS model.

The slim steering head is integrated into the frame structure and allows 42 degrees of lock. The steering head is fixed using a completely new layout of gusset plates which have considerably reduced the design width without affecting the stability of the frame.

The steering lock is also improved by placing the ignition lock in front of the handlebar.

Off-road, the small turning circle is useful when negotiating difficult terrain at walking pace.

The tubular space frame made from manganese-alloy steel integrates the engine as a load-bearing element.

The frame tubes join the engine using forged steel nodes. The rear of the frame is made from rectangular steel sections, connected by four special fasteners and carries the new 16-litre fuel tank, positioned under the seat.

This frame design allows the front part of the seat to be narrow allowing even shorter riders to have good control and balance, especially when on uneven ground.

Made-to-measure telescopic forks
Because of the very long 230 mm of front suspension travel, an upside-down telescopic fork is the best choice for the F800GS. The overlapping of the fixed and sliding tubes is large with this design, since the fixed tube diameter of 45 mm ensures excellent resistance to bending. Plastic deflectors combined with the front wheel covers provide protection against stones.

Aluminium swing arm at rear
The rear suspension is similarly robust. It is based on an aluminium arm, die-cast in a single piece. The F800GS uses a directly hinged central spring strut with 215 mm suspension travel.

Spring pre-load can be adjusted using a handwheel, so that the rear wheel suspension can easily be adjusted for one- and two-person use. The damping stroke of the suspension can also easily be adjusted to individual requirements.

Wheels and tyres fit for the job
The F800GS uses aluminium spoked wheels, 21 x 2.15 at the front and 17 x 4.25 at the rear. The front wheel size of 21-inches, usual for a machine in this class, gives greater riding stability because of the greater gyroscopic forces. Dual terrain style tyres are fitted as standard.

The F800GS has 90/90-21 tyres at the front and 150/70-17 items at the rear.

Braking systems matched to each model
The front wheel of the F 800 GS has two fully floating brake discs 300 mm in diameter and double-piston sliding callipers.

At the front, the steel-reinforced brake lines are routed so they do not push through the cockpit fairing when the telescopic fork is compressed. At the rear there is a 265 mm disc with single-piston sliding calliper.

Switchable two-channel ABS with improved rear wheel anti-hop detection
The F 800 GS may be optionally specified with two-channel ABS. The current generation of BMW Motorrad ABS has a compact design and low weight, and provides short braking distances.

The pressure modulator controls the optimum braking pressure in the regulating range via intake valves that are adjusted on a linear basis and is characterised by its very fast, fine regulating intervals. The valves have infinitely variable cross-section openings to ensure that the rider only perceives a slight pulsing in the brake levers.

The BMW Motorrad ABS offers expanded diagnosis functions: the wheel revolution sensors monitor their distance from the sensor wheel automatically and thus contribute to the vehicle's outstanding safety. The ABS can be switched off for off-road use if required.