2008 BMW G 450 X Sports Enduro
Concept, requirements and features
During the last 80 years BMW Motorrad has made off-road history time and time again. The marque is now more closely involved in off-road sport than ever and is launching an uncompromising, sport enduro for the attractive 450cc class.
The exclusively developed BMW G 450 X is an enduro sport for some of most demanding competitive racing in the world. It is a machine that is ready to compete the moment it leaves the factory.
The background to the development is the knowledge that competition-oriented enduro motorcycles represent a parameter with growth potential. Markets such as the USA, Australia and Spain already register – nearly traditional – stable sales in the off-road sector. BMW Motorrad wants to help shape and stimulate this (and other markets) for the long term. Smaller volume off-road motorcycles open the gateway to popular and professional motor sport as well as offering enough potential to help the young generation to discover the fascination of motorcycles.
The engine of the G 450 X features the latest fuel injection and computer-controlled three-way catalytic converter. It is Euro III homologated and already meets the rigorous current and future vehicle emissions standards for sports events and road vehicles. With these measures BMW Motorrad is taking a further step towards public acceptance of enduro sports. The patented, unrivalled technical features of the new BMW G 450 X make it a driving force that contributes to the advance of technological competition in its segment.
The introduction of the tough enduro BMW G 650 Xchallenge has already pointed the way: with a frame and swing arm layout for improved offroad traction, low weight, compact chassis, and dynamic engine. The G 450 X goes even further and BMW is not content with constructional features traditionally seen in the class.
High-tech solutions have been realised in the engine and chassis design, in keeping with BMW’s cross-country sporting tradition. It is a machine that will give the marque a fascinating and exclusive off-road profile.
The concept of the BMW G 450 X is based on keeping the mass concentrated as near as possible to the centre of gravity and realising a vehicle configuration that adapts perfectly to the requirements of off-road sport.
The central element of this concept is the amalgamation of the bearing axle of the rear-wheel swing arm with the axis of rotation of the driving pinion. This ensures that there is no change in the length of the chain on compression and rebound. The effects of the final drive on the vehicle’s response are therefore minimized.
Further consequences of this unequalled technical approach are a noticeably longer swing arm (for the same wheelbase as other machines) and, with it, maximum traction. This provides definite advantages in enduro sports which exert extreme demands on rider and machine.
Fundamental to the overall design is a saving in length through the alliance of the swinging bearing and pinion rotation axis. Not only does this enable a longer swing arm but the modern high-performance DOHC single-cylinder engine, with an output of 50PS, is able to be positioned further towards the rear. The cylinder has therefore been angled more acutely towards the front, thus creating space for long, straight intake tracts. In this way an ideal position was reached for the fuel injection nozzle and dual throttle valve fuel injection system. This contributed in adapting the engine to meet the requirements of the Euro III exhaust gas norm – without loss of performance.
Further concept advantages include optimum protection of the airbox and voluminous air flow because of its placement above the motor and in front of the seat. One consequence of the centralised concentration of masses close to the centre of gravity is that the 8.5-litre tank is under the seat. The filler manifold is located below an opening in the rear part of the seat. The reserve function is signaled by a warning lamp in the cockpit.
The starter is placed in front of the engine. The easily accessible battery is protected from dirt and sits directly behind the control head in the upper triangular frame. The air filter is a square, flat wet element fixed by a drawer mechanism that makes it easy, safe, clean, and extremely fast to change. For this,the right cosmetic tank cover (fixed with a quick-release fastener) is removed and the air filter drawer pulled out.
The intake funnel is positioned at the height of the control head whose high-lying position is advantageous in water splashes, or wherever there is heavy dust. The seat of the BMW G 450 X is made from special foam plastic. The foregoing of a cover, and not having a substructure or sump as its base, brings weight advantages.
Another distinctive construction feature is the relocation of the clutch directly onto the crankshaft. A position that enabled the ingenious frame construction – the frame tubes were placed directly ahead of the swing arm pivot, enabling maximum stiffness, minimum weight and minimal use of material. The cooler had sufficient space to be realised in one piece. This saved additional coolant hoses and reduced weight – important for an off-road motorcycle.
The development of the BMW G 450 X focusses on the ergonomic shape and design of the active driving configuration. From the steering head to the rear section of the seat the machine has an extremely slender width – exactly where the rider sits – and provides maximum freedom of movement. In a standing position, the rider benefits because of the absence of a tank. This point provides unrestrained clearance because the motorcycle is appreciably slimmer.
The G 450 X is the first BMW enduro to be uncompromisingly developed for professional competitive racing. The advantages of the unique construction are evident in rugged off-road conditions. These include the effective concentration of masses around the centre of gravity; the engine effects eliminated by the unique swing arm mounting; the resulting low wear of chain and pinion, and extreme handling reminiscent of a 250 series motocross motorcycle. Also notable are the prodigious tracking stability, low weight, powerful engine and the high-technology spring elements. These offer the ambitious enduro sports rider a number of package and design benefits in hard competition, plus limitless riding pleasure.
A dedicated team of specialist engineers and mechanics, who have also taken part in intensive off-road sport privately for many years, has developed this new model for BMW Motorrad under the motto “from passionate professionals for passionate professionals”.
The BMW G 450 X weighs about 40 kilogrammes less than the G 650 Xchallenge for roughly the same output and is perfectly tailored to the requirements of the ambitious and success-oriented enduro sports rider. As a completely special and absolutely exceptional motorcycle, the BMW G 450 X is a genuine sports machine that has all parts required for MOT approval as standard. This means that – unlike other vehicles in the class – it is possible to ride the BMW G 450 X to the track on public roads.
The innovative, patented technology of the single-cylinder sports enduro concept was put to the test in highly-competitive events throughout the 2007 season by experienced and successful racing professionals. These included such riders as Sascha Eckert, Simo Kirssi and Joël Smets who harmonised and developed the concept.
The motorcycle comes ready for off-road racing and competition and (with approval) public road use straight from the factory – without modification.
Thanks to great traction at low revs, smooth engine output, high revving, superior riding qualities such as extremely light handling, best balance in slow
“trial” sections, and enormous stability at high speed, the professional, experienced or novice enduro rider will have no difficulty in mastering the G 450 X motorcycle.
To corroborate the machine’s extremely sporty enduro qualities, BMW Motorrad’s works racing team has already taken part in different enduro sports during the test phase of the G 450 X. The team will continue racing it in the Enduro World Championship of the E2 class and/or the German Cross Country Championship (GCC).
The worldwide market introduction of the BMW G 450 X is scheduled for the middle of 2008.
Model designation -
BMW G 450 X
The model designation G stands for a new Generation of sporting motorcycles in the mid-range and lower capacity segments. It is distinguished by its consistent lightweight, easy handling, tracking stability, and safe riding qualities. For drive power, the focus is placed on powerful, cultivated, dependable and economic single-cylinder engines.
G stands symbolically for a well thought out General concept; perfection in the performance of the whole machine and for the harmony of all individual components. G also stands for Great riding qualities and pure unadulterated riding pleasure.
The range of possible uses of the G models covers a wide spectrum: from the light all-rounder, ideal for touring, to the agile supermoto performer and the robust hard enduro right up to the genuine sports enduro with competitive qualities. While the models of the 650 series are based on a common technical basis, the high performance G 450 X is the first machine of a motorcycle generation that proves to be uncompromisingly competitive and success oriented. Common to all G models is the high-grade substance of the product and legendary BMW quality – independent of where it is produced.
Specially tailored to differing riding styles, and the abilities of the G 450 X, exclusive training and preparation will progressively supplement the new motorcycle.
From a technical point of view the BMW G 450 X has no forerunners. It is a brand-new development where features such as weight saving and an uncompromising configuration – for the requirements of competition-oriented off-road racing – were at the forefront of the specification.
Enduro racing places enormous stress on materials. The transition to motocross sport is fluid and the machines, which are tuned to the limits of performance, are pushed to the limit so that technology can satisfy the highest demands.
Due to the extreme range of use, the trials of the G 450 X were extremely complex and totally new paths had to be taken in some areas. The testing included the toughest enduro performance with metre-high jumps; freezing cold and extreme heat; water splashes, and continuous racing
in extremely dusty conditions with sand and stone impacts. The bike must be able to withstand all these conditions reliably and sustainably. Hardly any other type of motorcycle is confronted with such requirements in this combination.
The proving programme primarily included testing in a real competitive environment and numerous test bench tests. Trials on special test tracks were correspondingly extensive and intensive. From the very outset this meant the BMW G 450 X had to prove itself in the environment in which it intends to compete. This took place on national and international enduro and motocross racing tracks where the slightest weakness of rider or machine can lead to defeat or failure.
Long-term trials on terrain in Spain and Italy continued the overall programme right up to serial production.
The 449 cc single-cylinder DOHC 4-stroke motor of the G 450 X was developed by BMW. The compact cylinder head of the short-stroke four-valve unit houses the technical elements of the K 1200 S. For example, the intake valves are operated by follower valves, and the outlet control is implemented by tappets. This is a space-saving configuration distinguished by high engine speeds. Optimum performance meets the requirements of the Euro III exhaust gas norm and is realised by fuel-injection with oxygen sensor regulation and a dual throttle valve system which ensure that the engine reacts more sensitively to gas commands. The crankshaft and conrod are fitted with rolling bearings and the weight-optimised two-ring piston is forged.
A balance shaft effectively reduces the vibrations typical of a single-cylinder engine. The constant mesh five-speed gearbox – standard throughout the 450 series – was widely staggered for optimum connections while racing. The primary coupling sits directly on the crankshaft and is configured as a wet clutch with a clutch diaphragm. In contast to conventional concepts, the BMW G 450 X clutch is considerably more compact and has a smaller diameter with the same number of discs. Contrary to the conventional geared-down clutches, this is possible because the clutch only needs to transmit a correspondingly reduced torque on the transmission input shaft. The clutch is operated by a cable.
The engine is fed with oil by a wet sump lubrication system. Two oil pumps, a pressure pump and a suction pump use the same volumes of oil to lubricate the gearbox and the crankshaft. The two integrated oil sieves and oil filter are easy to access from the left side of the engine. The volume of oil – approximately one litre – can be checked via an inspection glass.
An intermediate shaft with integrated ventilation function transfers the power from the crankshaft to the gearbox and this means that the crankshaft of the G 450 X engine rotates backwards. The cylinder is tilted forward by approxi-mately 30 degrees, enabling the centre of gravity to be moved in the direction of the front wheel thereby assisting the suspension. A further advantage of tilting the cylinder is the creation of space for the intake air ducting that can now come vertically from above, and virtually straight, promoting optimum performance.
The engine of the BMW G 450 X, condensed into 12 : 1, is started by an electric starter; an additional kickstart is unnecessary thanks to a powerful battery and fuel-injection. An automatic decompression function with a centrifugal force valve lifter reduces the power demanded by the starter. Even when the machine has to travel for longer periods at higher revs in difficult and slow off-road sections, the engine is never excessively thermally loaded thanks to its large-volume, single-piece water cooler. A fan behind the cooler provides sufficient air flow rate at low flow speeds.
The series exhaust system is made of stainless steel and the catalytic converter is fitted in the silencer (absorption silencer). For exclusive use in competitive racing, optional sporting silencers are offered as special equipment and it is possible to switch to the extreme race mapping stored in the engine control unit.
Despite the powerful alternator and electric starter, the high-performance engine of the BMW G 450 X weighs no more than the aggregate of competitor motorcycles (less than 30 kilogrammes). The exact power and torque data are not yet fixed.
The chassis of the BMW G 450 X is a completely new development that uses selected high-quality components and materials. BMW Motorrad’s years of enduro experience aided the development of the chassis. The main consideration in the geometry and overall configuration of the chassis was to meet the especially high demands of off-road racing. The results are excellent all-terrain properties with ease of handling, great manoeuvrability and extreme tracking stability.
Innovative frame concept
The frame layout is based on the experiences of the development engineers; the know-how from competitive racing and its attendant research and development work. The knowledge gained from earlier rally sport activities was also incorporated. The frame of the BMW G 450 X differs in principle from all the constructions of competitor machines. In the main it consists of thin-walled, but high-strength stainless steel precision tubes and is welded to the node points with forged parts deployed for the purpose. No additional surface treatment is necessary. The entire main frame weighs a mere 8.6 kilogrammes and is distinguished by excellent rigitity.
The lower bow of the frame tubes runs directly from the swinging axle straight to the steering head. The upper bow creates a direct connection between the suspension strut mount and steering head. The wheel forces are braced centrally on the frame over the suspension strut so that the light rear frame is bolted to the main frame and is formed by aluminium square profiles and only needs to bear the weight of the rider. All in all this construction enables the optimum flow of force, requiring minimum use of material, and allows an unrivalled rigidity to weight ratio.
The 18-inch rear wheel is suspended in a robust dimensional two-arm swing arm made from aluminium square profiles which supports a directly linked Öhlins central suspension strut with a generous spring travel of 320 mm. This high-technology element is variably adjustable in pressure and outward stroke damping as well as in the spring pre-tension. The suspension of the 21-inch front wheel is undertaken by 45mm upside-down forks by Marzocchi. This absorbs even the roughest ruts with a spring travel of 300mm and is fully adjustable.
A powerful brake system with double-piston floating caliper, from Brembo, ensures the deceleration of the BMW G 450 X. The front single brake disc has a diameter of 260mm, and the rear disc measures 220mm.
In order to live up to the harshest off-road conditions, the BMW G 450 X has a light, impact resistant and highly stable plastic underride protection fitted as standard. This has already proved itself in racing. The motorcycle also has a double-butted Magura aluminium handlebar that guarantees optimum control on all terrain.
Patented swing arm mount
The real finesse in the chassis sector and a unique feature of the BMW G 450 X is the coaxial mount of the swing arm and chain pinion. The swing arm pivot has been mounted through the hollow gearbox outlet so that there is no change in the length of the chain on compression and rebound over the entire spring travel. The chain tension remains constant, independent of the compression position; the pinion, chain and chain ring are subject to less wear than in conventional constructions. A positive effect on the riding characteristics is that the effect of changing loads on the powertrain is now noticeably reduced.
Thanks to the patented coaxial mounting of the swing arm and drive chain pinion, plus a wheelbase at competition level, the swing arm is 30mm longer, markedly improving traction properties. The rear wheel remains more in contact with the ground in all situations and retaining the driving force on all types of terrain. Also, compared with other machines, a significantly greater length adjustment range of the rear wheel results. This allows different pinion chain ring combinations on the same chain.
When a pinion has to be replaced, the swing arm must be removed. However, in comparison to conventional concepts, this is not a particularly time consuming task. An experienced mechanic can replace the pinion in about 15 minutes and, because of the much lower wear of the entire final drive, the pinion needs to be replaced less often then on other competition machines.
The look of the BMW G 450 X is unmistakenly BMW Motorrad. The dynamic ‘flyline’ allows the new motorcycle to be identified as a typical member of the BMW enduro world. The most striking element is the typical family beak – the most distinguishing characteristic shared by all GS models.
The visual appearance also expresses pure sporting performance with associated aggression. This results in the look and feel of a fascinating vehicle that suggests the right to ride and to win in competitive races.
The colour concept of the G 450 X is oriented to the G 650 Xchallenge.
The standard colour is ‘racing white’ with blue accents, typical of BMW, which highlights the affiliation to the G model family and the new, sporty enduro line from BMW.
The exact technical data of the BMW G 450 X has not yet been finalised as the machine will not be available to purchase until the middle of 2008. The maximum output is around 37kW (50PS) with a best torque value of approximately 48Nm. The overall weight with full tank is approximately 120kg which means that the BMW G 450 X is lighter than the current best weight values in its class. This value is all the more impressive because the machine boasts fuel injection, catalytic converter, electric starter and Euro III homologation. The exact geometrical data of the chassis is subject to last minute fine tuning and will be announced at a later date.