The new BMW G 650 Xchallenge is one of three models presented by BMW in Europe simultaneously last October. The other models, G 650 Xmoto and G 650 Xcountry are not offered in Australia.

The new G 650 models were developed in association with Aprilia and are manufactured in Italy. The engine is built by Rotax to BMW specifications.

Powertrain.
The engine is a weight optimised development of the proven and familiar liquid-cooled, fuel-injected F 650 GS engine, now 2 kg lighter. Engine output increases by 3 bhp to 53 bhp or 39 kW at 7,000 rpm. Torque is 60 Nm at 5,250 rpm, and the engine complies with EU 3 restrictions on emissions.

With a 100 mm bore and 83 mm stroke, the capacity is 652 cc exactly.

The double-overhead camshaft drives two intake and two exhaust valves, while twin spark plugs extract maximum torque. The second plug is retarded slightly at higher revs to ensure a cleaner burn.

A die-cast aluminium crankcase holds the crank in plain bearings and other shafts run in ball bearings. A balance shaft virtually eliminates typical 650 single cylinder vibrations.

The new dry sump lubrication means a very small oil pan, with two pumps in the side of the block; the smaller to pump oil around the engine and the larger to pump returned oil through the filter.

The wet clutch has seven friction and seven steel plates. The magnesium clutch cover is painted black, as is the redesigned alternator cover. This gives the G 650 engine a different look to that of the F 650.

The familiar dual-shaft five-speed gearbox is of conventional design, and it drives the rear wheel via an O-ring chain.

Final drive ratio on the chain sprocket has been modified compared with the proven and reliable F 650, with a 15-tooth pinion and a 47-tooth sprocket fitted to the G 650 Xchallenge.

Thanks to the very frugal and efficient engine, the 9.5-litre fuel tank gives a range of 200 km plus, depending on riding conditions.

Service intervals of 10,000 km are unusually long for this class of motorcycle, underlining its inherent durability.

Chassis.
The G 650 Xchallenge uses an all new chassis and suspension designed for excellent riding off-road. A standard aluminium sump guard is bolted to the underside of the engine, underlining its taste for off-road work.

The suspension comprises top grade components including upside down telescopic forks with 270 mm travel. The 45 mm stanchions move within gold anodised sliders and are protected against dirt and wear by black plastic covers.

The rear air suspension strut also allows 270 mm of travel.

The BMW Motorrad Air Damping System delivers a pneumatic rear air suspension strut similar to that of the BMW HP2 Enduro. For the G 650 Xchallenge damping and suspension are determined by air pressure only. Two damping levels may be selected via the adjuster and the height of the bike is determined by air pressure inside the strut. A standard valve (tyre type) allows the air pressure to be regulated, and a pump is clipped under the seat.

During compression and rebound, air travels through defined passages between the cylinder space and rubber bellows. Compression of air creates a progressive suspension as far as the elastic, plastic bump stops.

Benefits of the BMW Motorrad Air Damping System are:

• “Natural” progression of spring rates under high load (with growing pressure within the system).
• Reliable and smooth operation minimising the risk of the suspension giving way (physical law of gases: pressure increases as a function of temperature). 
• “Natural” progression of the damping effect under high loads (the viscosity of air increases as a function of temperature).
• Frequency-dependent, selective damping effect.
• Resistant to overheating (no temperature-induced weakening of the damping effect under high loads).
• Simple option to adjust the dampers to the load carried. 
• Low weight of the entire system and its components.
• Individual adjustment and set-up of the suspension matched to the rider’s weight and the load carried by means of a spirit level presenting the normal position and trim of the motorcycle.
• The reduction in unsprung masses also improves spring response and traction on the rear wheel. The spring strut is sealed hermetically and is therefore protected from contamination. It can be re-pressurised simply via the hand pump carried on board. 

Frame.
The split-bridge main frame is tubular steel, powder coated with a grey 'graphitan' finish.

The engine is a load bearing unit. Reinforced high-strength steel sections extending from the steering head are bolted to two cast aluminium mouldings and the cylinder head.

The rear suspension strut mount – a forged aluminium component, is located centrally behind the engine. It is rigidly bolted to the cylinder head and the two lower frame sections, and forms a solid support for the rear suspension strut and frame section.

The rear frame section is made of square aluminium tube, supported on the main frame via rigid braces. At the top it is bolted to the suspension strut mount.

The rear suspension swing arm is cast aluminium finished in 'graphitan'. Bearing journals are located on each side and rigidly bolted to the frame. The swing arm is supported in the frame via needle bearings on the journal.

Wheels, brakes.
Dual-purpose tyres are fitted to spoked wheels front and rear. The front wheel is a 21" (x 1.6") item while the rear is 18" (x 2.5").

Single ‘Wave’ pattern brake discs are fitted front and rear, the design incorporating a useful self-cleaning feature, ideal for off-road use. Steel braided brake lines ensure reliable stopping.

The front disc is 300 mm in diameter and has a two-piston floating calliper while the rear is a 240 mm disc with a single piston floating calliper. Both callipers are anodised in gold further highlighting the premium nature of the machine.

The optional ABS unit is shared with the BMW F 800 and R 1200 S models and may be disengaged for riding off-road.

The G 650 Xchallenge is fitted with conventional electrics with relays and fuses.

Styling.
The G 650 Xchallenge is styled to appeal to the serious off-road trail bike enthusiast. It has a GS-like beak front mudguard that appears to continue in an unbroken line into the ‘tank’ cover and on into the long flat seat, and then to the tail cover panel.

Seat height is 950 mm in the normal position, and wide footrests ensure a safe riding position especially when up on the pegs.

An upswept stainless steel muffler gives a typical trail bike look. The exhaust system includes an oxygen sensor and three-way catalytic converter in order to meet clean EU 3 emission levels.

The LED tail light cluster of the Xchallenge can be easily removed. The 18 diodes dim when used as tail lights and brighten when used as a stop light.

Viewed from the front the G 650 Xchallenge has a BMW trademark asymmetrical H4 freeform headlamp unit and white turn indicators, while a digital instrument panel and small windshield sit ahead of the over-size alloy handlebars for strength and authenticity.

New electrical switchgear is fitted to the G 650 Xchallenge and is deliberately compact and reduced to the most essential items.

The G 650 Xchallenge is the first BMW to come without any analogue instrumentation. The display shows the speed in large digital numerals, while current mileage alternates between one of two trip meters, clock and battery voltage, all of which can be scrolled by pressing the MODE button.

Pressing MODE and SET together allows different tyre diameters to be selected. LEDs are used as indicator and warning lamps.

Accessories available for the BMW G 650 Xchallenge.

• Off-road headlamp protection grille.
• Aluminium cover for rear brake fluid reservoir.
• Aluminium chain guard and sprocket cover.
• Small engine protection bars.
• Handlebar impact cushion.
• Luggage rack.
• Rear bag.
• Tank bag.
• Pillion kit (foot pegs, grab handles).
• 12 V socket.
• Navigation mounting bracket.
• Low seat.