Motorcycle specifications BMWG 450 X 2008 Muscular excursion

BMW knows how to surprise, even going so far as to explore terrain far removed from its public. We know the manufacturer is formidable when it comes to on-road machines, and just as formidable when it comes to exploring off-road terrain. The 1200 GS and Adventure are no strangers to this ritual. Now the brand is taking a more radical route, with a pure enduro machine. The G 450 X is in no way an appeal to the category, but presents itself as a first-rate competitor for discerning enthusiasts.

the engine, featuring state-of-the-art petrol injection and a three-way catalytic converter with lambda probe, is Euro 3 approved. The unique, patented technical refinements of the new BMW G 450 X are providing impetus and should help drive technological competition in this market segment.

the BMW G 450 X concept is based on two objectives: to concentrate mass as close as possible to the center of gravity, and to create a chassis perfectly suited to the demands of off-road sports. Aligning the rear swingarm housing axis with the drive pinion axis is a central element of the resulting design. This eliminates chain tension variations in both compression and rebound travel, and minimizes the influence of the final drive on handling. With the same wheelbase as the competition, this unprecedented technical choice has also made it possible to adopt a significantly longer swingarm, with the resultant advantages of maximum driveability.

in terms of overall design, the space freed up in the longitudinal axis by aligning the swingarm and pinion axles is an essential element. Not only has this enabled the use of a longer swingarm, it has also allowed the high-performance single-cylinder engine to be moved back, a modern double-actuated motor delivering around 50 hp - 40.8 hp in standard configuration. This enabled the cylinder to be tilted further forward, freeing up space for long, straight intake ducts. At the same time, the injector and twin-throttle system were optimally positioned. This has helped to adapt the engine to Euro III emissions standards without any loss of power, which is far from the rule in this class of motorcycle. Other advantages of this design: the airbox is housed in a protected, aerodynamically favorable position above the engine, in front of the seat. The 8.5-liter fuel tank is housed under the seat, in strict compliance with the principle of concentrating mass close to the center of gravity. The filler neck is located under an opening in the rear of the seat. The reserve function is indicated by a warning light in the cockpit.

the starter motor is located in front of the engine, while the battery is located in the upper triangle of the frame, directly behind the steering head, where it is protected from dirt and easily accessible. The air filter consists of a flat, rectangular wet element fixed by a drawer mechanism. Replacing it is easy, safe, clean and ultra-fast: simply remove the right-hand quick-fit side cover and pull out the air filter drawer.

the air intake for the filter is at the height of the steering head, a position that offers advantages when fording or when there's a lot of dust. The seat of the BMW G 450 X is made from a single piece of special honeycomb plastic. It is not clad and has no underlying structure or shell, which optimizes its weight.

moving the clutch directly onto the crankshaft is another original design feature. This arrangement has enabled a refined frame design: the frame tubes can run in a straight line from the swingarm housing to the steering head. The result is maximum rigidity with minimum weight and minimum material requirements. At the same time, it offers advantages for the radiator. With more space at its disposal, the radiator can be made in one piece, eliminating the need for additional piping and thus reducing weight.

during the development of the BMW G 450 X, engineers placed great emphasis on ergonomic design for active driving. From the steering head to the rear of the seat, the bike is extremely slim, giving the rider maximum freedom of movement. This advantage is particularly noticeable when the rider stands on the footrests, as the relocation of the fuel tank has freed up space, making the bike considerably narrower in the area normally occupied by the tank.

in this configuration, the G 450 X is the first BMW trail bike to have been rigorously designed for professional competition use. In the field, it will play to the strengths of its unique design like no other machine. The efficient concentration of mass around the center of gravity, the elimination of power transmission influences thanks to the unique swingarm housing, the resulting reduced chain and sprocket wear, the extreme handling reminiscent of athe elimination of power transmission influences thanks to the unique swingarm housing, the resulting reduced chain and sprocket wear, the extreme handling reminiscent of a 250 cm3 motocross bike and, at the same time, the excellent handling, low weight, powerful engine and top-of-the-range suspension components offer the enduro rider with sporting ambitions real advantages in competition and boundless pleasure on the handlebars. Given the possibilities it opens up to its rider, the G 450 X is the best-performing off-road BMW in its history in rigorous off-road use.

the innovative, patented, single-cylinder trail-sport technology was put to the test throughout 2007 in all the leading events, and thus the ruthlessexperienced riders such as Sascha Eckert, Simo Kirssi and Joël Smets, who helped perfect and fine-tune the settings. Today, the motorcycle is presented at the highest level, ready to take part in off-road races from the factory, and with homologation for public road traffic without having to be adapted beforehand.

distinguished by good acceleration from low revs, linear power delivery and enormouspower delivery and enormous ease of revving, with superb road-holding qualities and extreme handling this racing bike is easy to ride, not only for real pros or experienced enduro riders, but also for those new to the sport.

test program.

given the extreme range of use, putting the G 450 X through its paces proved to be a very complex task, and in some cases required a completely new approach. Testing included relentless enduro missions involving meter-high jumps, freezing cold and tropical heat, ford crossings and marathons in an extremely dusty, sandy and stony environment. The motorcycle must be able to withstand all these conditions reliably and over the long term. Hardly any other type of motorcycle has to cope with such an amalgam of stresses. That's why the test campaign was so extensive and intense. In addition to numerous bench tests and tests on specific test tracks, it also included testing in real-life competitions. Right from the start, the BMW G 450 X had to prove itself in the places where it would later compete for titles: on the tracks of national and international enduro and cross-country events, where the slightest weakness in both man and machine could result in failure or retirement. Off-road endurance tests in Spain and Italy completed the program before the bike was validated for series production.

mechanical assembly.

the 449 cubic centimetre, single-cylinder, four-stroke, twin overhead camshaft engine powering the G 450 X was developed by BMW. The four-valve, short-stroke engine's compact cylinder head houses technical features borrowed from the K 1200 S: intake valves are actuated by a latch, while exhaust valves are operated by a tappet. A space-saving configuration for high revs. Optimum performance and compliance with Euro III emissions standards are ensured by lambda-controlled petrol injection and two throttle valves fitted as standard. These enable the engine to react even more sensitively to throttle movements. Crankshaft and connecting rod are bearing-mounted, while the lightened two-ring piston is die-forged.

a balance shaft effectively reduces the vibrations inherent in single-cylinder engines. The fork-and-clutch five-speed gearbox, typical of the 450 cm3 class, is wide-ratio to ensure optimum gear shifting on the racetrack, always in contact with power. The primary clutch is housed directly on the crankshaft, and is of the oil-bath diaphragm type. Compared to conventional designs, the clutch on the BMW G 450 X is considerably more compact, with a smaller diameter and the same number of discs. This advantage is made possible by the fact that the torque to be transmitted is lower than that acting on conventional geared clutches housed on the gearbox input shaft. The clutch is cable-actuated.

the motor is supplied with oil via a wet sump lubrication system. Two oil pumps - one delivery and one suction - draw on the same volume of oil to lubricate the gearbox on the one hand, and the crankshaft on the other. The two integrated oil strainers and oil filter are easily accessible for replacement from the left-hand side of the engine. A transparent sight glass allows you to check the oil level, which is approximately one liter.

transmission from crankshaft to gearbox is via an intermediate shaft with integrated degassing function. This means that the crankshaft of the G 450 X engine turns in the opposite direction. The cylinder is tilted forward by around 30 degrees. This shifts the center of gravity towards the front wheel, benefiting wheel steering. In addition, the cylinder's inclination frees up space, enabling the intake ducts to be straightened, so that, coming from above, they occupy a straight vertical position that benefits power.

the BMW G 450 X's 12:1 volumetric ratio engine is started by an electric starter.lectric starter; given the reliable starting performance provided by the high-performance battery and fuel injection, a kick starter was not required. An automatic decompression function with centrifugal valve lifter reduces the starter's energy requirement. Even if the bike is taken through long, difficult off-road sections at high revs and very low speeds, the engine will never suffer from excessive thermal stress, thanks to its voluminous one-piece radiator. A standard fan housed behind the radiator ensures sufficient airflow at low flow speeds.

the standard exhaust system is made of stainless steel, with the catalytic converter integrated into the rear silencer (absorption silencer). For exclusive use in competition, the range of accessories offers optional sport rear silencers, with the option of activating an extreme "racing" mapping, stored in the engine management system.

although equipped with a powerful alternator and electric starter, the engine powering the BMW G 450 X weighs no more than the competition's units (less than 30 kg).

cycle.

the chassis of the BMW G 450 X is a completely new design, using particularly high-end components and materials. BMW Motorrad's many years of enduro experience went into the development of the chassis. As for the geometry and overall design, the aim was to meet the particularly demanding requirements of off-road racing. The result: excellent off-road qualities combined with top-level handling, agility and directional stability.

innovative frame concept.

the frame concept is based on the experience of the design engineers, experience gained in competition, and parallel research and development work. We were also able to draw on experience gained from past rally activities. The frame of the BMW G 450 X, for example, is an entirely new design, fundamentally different from any of its competitors. It's essentially made of thin-walled, yet highly resistant stainless steel precision tubing, welded to forged connections at the gusset plates. No additional surface treatment is required. The main frame weighs just 8.6 kilograms overall, and boasts excellent rigidity.

viewed from the side, the lower frame tube runs in a straight line from the swingarm to the steering head. The arched top tube, on the other hand, creates a direct link between the upper housing of the spring/shock unit and the steering head. This means that forces acting on the rear wheel are transmitted directly to the main frame via the spring/damper unit, so that the lightweight rear frame made of rectangular-section aluminum tubing bolted to the main frame only has to support the rider's weight. Overall, this design optimizes the flow of forces while requiring less material, resulting in a stiffness-to-weight ratio unmatched to date.

the 18-inch rear wheel is guided by a double swingarm formed by generously dimensioned aluminum box-section profiles. The swingarm is supported by a directly articulated Öhlins central spring/damper unit. This top-of-the-range unit offers a generous 320 mm of travel, allowing the shock absorber to be adjusted for compression and rebound, as well as spring preload, in a wide range of positions. The 21-inch front wheel is guided by a 45-mm inverted Marzocchi fork which, with 300 mm of travel, filters out even the roughest bumps, and is also fully adjustable.

a high-performance Brembo double-piston floating caliper braking system ensures the BMW G 450 X's deceleration. The front brake disc (single-disc) is 260 mm in diameter, while the rear disc is 220 mm. An ABS is unusual in this class, and given the G 450 X's terrain, such a braking assistant would be counter-productive on this bike.

to meet the demands of the toughest terrain, the BMW G 450 X is fitted as standard with a lightweighta lightweight, resilient and highly stable synthetic shoe that has already proved its worth in racing. It is also equipped with Magura tapered aluminum handlebars for optimum control of the bike on any track.

patented swingarm housing.

the coaxial housing of the swingarm and chain sprocket is the real refinement of the chassis, and at the same time a feature that only the BMW G 450 X can boast: the swingarm axis passes through the hollow shaft of the gearbox, so that the chain undergoes no change in length during compression or rebound. Regardless of travel, chain tension remains constant, and pinion, chain and sprocket wear is lower than with conventional designs. The reduced influence of load alternation on the drive train is minimized, which has a positive effect on dynamic qualities.

although the wheelbase is the same as that of the competition, the coaxial housing of the swingarm and chain sprocketalthough the wheelbase is the same as that of the competition, the coaxial housing of the swingarm and chain sprocket, for which a patent has been filed, has made it possible to use a swingarm some 30 millimetres longer, which translates into significant driveability benefits. Whatever the situation, the rear wheel maintains contact with the ground for longer and transmits torque better on the track. What's more, compared with the competition, the rear wheel's range of adjustment on the longitudinal axis is considerably greater. Using different pinion/sprocket combinations with the same chain is therefore no problem at all.

if it's necessary to change the sprocket, the swingarm has to be dismantled, but this is a rather quick operation compared to conventional designs. A skilled mechanic will need no more than around 15 minutes to replace the pinion. Given the significantly lower wear on the entire secondary drive train, the pinion also needs to be replaced less often than on the competition's.

design.

the look of the BMW G 450 X reveals at first glance that this is a BMW Motorrad motorcycle. The "flyline", a dynamic line when viewed from the side, identifies the new bike as a typical member of BMW's enduro universe, the most striking element being the family's typical "duckbill" mudguard, which is at the same time the common distinguishing feature of all GS models.

Image and info credits: BMW