BMW G 450 X Enduro

by Dave · November 8, 2007

BMW introduces its first 450cc off road, race-bred motorcycle, the G 450 X

The new BMW G 450 X in brief:
• All new competition-bred sports enduro.
• Lightweight, compact chassis, dynamic engine
• Advanced, water-cooled, single-cylinder DOHC four-stroke, complete with balancer shaft, developed by BMW.
• Electric start, fuel-injection, Euro III compliant, race mapping for competition.
• Wet clutch, mounted on crankshaft, five-speed gearbox.
• Stainless steel tube frame weighs 8.6 kg.
• Low centre of gravity, centralised mass, 8.5-litre fuel tank under seat.
• Unique integral swing arm pivot and counter shaft.
• 45 mm Marzocchi USD front forks with 300 mm travel.
• Öhlins rear damper suspension with 320 mm of travel.
• Brembo brakes, double-piston floating calliper, single front disc, 260 mm front and 220 mm rear
• On sale worldwide (inc Australia) in 2008.

The new BMW G 450 X. From the showroom floor to the start line.

BMW introduces its first 450cc off road, race-bred motorcycle, the G 450 X. It has been developed in competition to provide the ultimate performance for racing as well as for the enthusiast enduro rider. BMW Motorrad is not new to competition or off-road racing. But now a new chapter in the company’s history opens with the G 450 X. Following in the wheel tracks of the BMW HP2 Enduro and HP2 Megamoto, both of which have proven their mettle in competition in the past year, the race-developed 450cc sports enduro prototype is now revealed as the all new competition-blooded G 450 X.

In fact the new BMW G 450 X has been developed for the most demanding competitive races in the world. It is a machine that is ready to race direct from the factory. Competition-bred enduro motorcycles represent a key growth market for BMW, especially in markets such as the USA, Australia and Spain, locations where BMW already has a stable footprint. This will be enhanced with volume sales of smaller capacity off-road machines ready to do battle in popular and professional motorsports environments and at the same time bring more younger riders to the brand.

The G 450 X engine is equipped with the latest generation fuel injection and boasts a computer-controlled three-way catalytic converter which is Euro III homologated. It meets emission requirements, which are growing more and more stringent each year. BMW expects the G 450 X will contribute further to the growth of the sports enduro market, especially given the high level of mechanical innovation it boasts. The patented, unrivalled technical features of the new BMW G 450 X make it a driving force in sports enduro design and contribute to the advancement of technological competition in this segment. The introduction of the BMW G 650 Xchallenge has already pointed the way with a frame and swing arm layout for improved off road traction, low weight, compact chassis, and dynamic engine. Now BMW Motorrad goes even further with the BMW G 450 X. Typically, BMW was not content to simply copy features traditionally seen in this class.

The result is a new machine that delivers high-tech innovation in both engine and chassis, to deliver unique riding excitement for sports enduro fans. Weight saving was a key focus point for the development team, along with a centralised mass concentrated around the low centre of gravity. Key to the achievement of this is the combination of the swing arm pivot with the axis of rotation for the counter shaft. The result is there is no change in chain length through the entire rear suspension stroke, minimizing the effects of the final drive on the machine’s response. As a further result, the swing arm can be longer for enhanced traction but without compromising the wheelbase, to ensure suitable agility on tight tracks.

Maximum traction means maximum forward motion, critical in competition. The swing arm design allows the motor to be mounted further back and acutely angled, a double benefit being long, straight and vertical inlet tracts. The engine is a high performance DOHC single-cylinder four-stroke that produces 37 KW (50 PS) and 48 Nm of torque (provisional figures only). As a result of the engine lean angle, the fuel injection nozzle and dual throttle valve fuel injection system is also well placed, an important additional benefit being the engine is able to meet the requirements of the Euro III exhaust gas level without loss of performance. Few rivals can boast such emission cleanliness. The design also allows for optimal mounting for the air box ahead of the motor in front of the seat, while the 8.5-litre fuel tank is placed under the rider’s seat, further centralising the masses close to the centre of gravity.

The starter is placed in front of the engine; the battery is protected from dirt and easily accessible directly behind the steering head in the upper triangular frame. The air filter is a square, flat foam element, fixed by a drawer mechanism that makes it very 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 is pulled out. The intake funnel is positioned at the height of the steering head whose high-up position is advantageous in water splashes or wherever there is heavy dust.

The seat of the BMW G 450 X is made from a special foam composite. Foregoing a cover and not having a substructure as its base brings weight advantages. Another distinctive construction feature is the relocation of the clutch directly onto the crankshaft. A position that enabled an ingenious frame construction: The frame tubes were placed straight ahead of the swing arm pivot, bringing maximum stiffness at the same time as minimum weight and lowest use of material. It also allowed the radiator to be mounted close to the engine removing the need for additional coolant hoses or additional coolant, which of course adds weight.

The development of the BMW G 450 X focuses on the ergonomic shape and design of the active driving configuration. Starting from the steering head to the rear section of the seat, the machine is extremely narrow, offering maximum freedom of movement. The lack of a traditional fuel tank allows a long flat seat providing exceptional range of motion while attacking technical terrain. The BMW G 450 X has been designed for professional competition right from the start. The innovative swing-arm, lightweight low-wear chain drive and low centre of gravity conspire to make the G 450 X feel as nimble as a 250 cc motocross machine with plenty of stability. The low weight and powerful engine combined with high-technology suspension deliver an exciting experience for the sports enduro rider. A dedicated team of specialist engineers and mechanics, who have also taken part in intensive off-road sport privately for many years, developed this new model for BMW Motorrad under the motto “from passionate professionals for passionate professionals”.

The BMW G 450 X builds on the expertise already incorporated into the BMW family by the G 650 Xchallenge, though saving 40 kg over the larger-engined machine. The G 450 X meets Australian Design Rules, it can be road registered, allowing it to be used legally on public land.

BMW G 450 X: Race bred through 2007.

The innovative, patented technology of the single-cylinder sports enduro concept was put to the test in all relevant highly-competitive events through-out the 2007 season by experienced and successful racing professionals such as Sascha Eckert, Simo Kirssi and Joël Smets. Their input helped finalise the concept as well as prove the integrity of the machine in world-class competition. Now the G 450 X is ready to compete at the highest levels in the hands of privateers.

The BMW G 450 X delivers excellent traction at low revs, a smooth, high-revving engine, superior riding qualities and extremely light handling for perfect balance in tight, technical terrain. It is suitable both for professional enduro riders as well as the enthusiast weekend warrior. Following a season testing and proving the G 450 X prototype in competition, the BMW Motorrad Motorsport team plans to continue to campaign the machine in the E2 class of the World Enduro Championship and the German Cross Country Championship (GCC).

The worldwide market introduction of the BMW G 450 X , including Australia, is scheduled for the middle of 2008. Top of Page 2. Welcome to the New Generation. BMW G 450 X. The model designation G stands for a new ‘G’eneration of sporty motorcycles, distinguished by consistent lightweight, easy handling, tracking stability and safe riding qualities. Power comes from a dependable and economical single cylinder engine with plenty of performance. G stands symbolically for a well thought out general concept and perfection down to the last detail, for the performance of the whole machine, for the masterful harmony of all individual components in respect to an impressive whole. 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 (G 650 Country) to the agile supermoto performer (G 650 Xmoto) and the robust enduro (G 650 Xchallenge) up to the genuine sports enduro with competitive qualities (G 450 X). While G 650 X models are based on a common technical basis, they are differentiated by configuration and unique individual product features determined by their respective purpose, the high performance G 450 X is the first representative of a motorcycle generation that shows itself to be uncompromisingly competitive and success oriented, representing the sporty spearhead of the G-series as a result.

Common to all G models is the high-grade substance of the product and expected BMW quality. Top of Page 3. The new G 450 X. Development, Technology and Design. 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 plus perfect and uncompromising configuration to the requirements of the competition-oriented off road racing were at the forefront of the specification during development. Test programme. Enduro racing places an enormous stress on the materials. The transition to motocross sport is fluid; machines tuned to the limits of performance are strained to the limits so their technology must satisfy the highest demands. Due to the extreme range of use, testing the G 450 X was extremely complex and totally new paths had to be taken in some areas.

The testing included the toughest enduro performance with motocross jumps, freezing cold up to extreme heat, bog holes and continuous racing in extremely dusty surroundings. The machine 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 testing programme primarily included testing in a real competitive environment as well as numerous bench tests and sessions 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 its natural environment; competition. That is why the prototypes were seen in German national and international enduro and motocross racing where the slightest weakness of rider or machine can lead to defeat or failure.

Long-term testing in Spain and Italy rounded off the overall programme until sign-off for serial production was achieved.

Engine.

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 power unit houses the technical elements of the K 1200 S: for example, the intake valves are operated by follower valves; the outlet control is implemented by tappets. A space-saving configuration distinguished by high engine speeds. Optimum performance that meets the requirements of the Euro III exhaust gas requirements is realised by fuel injection with oxygen sensor regulation and a dual throttle valve system which ensure that the engine reacts more sensitively to throttle commands.

The crankshaft and conrod are fitted with roller 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 was widely staggered for optimum performance in racing. The primary coupling sits directly on the crankshaft and is configured as a wet clutch with a clutch diaphragm. In contrast 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 for replacement. Just one-litre of oil is used for lubrication, with a sight-glass allowing easy checking. An intermediate shaft with integrated ventilation function transfers the power from the crankshaft to the gearbox and means that the crankshaft of the G450X engine turns backwards. The cylinder is tilted forward by approximately 30 degrees, enabling the centre of gravity to be moved in the direction of the front wheel thereby benefiting 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 BMW G 450 X engine runs a 12:1 compression ratio and uses an electric starter; thanks to a powerful battery and reliable 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 radiator. A bespoke fan hides behind the cooler to provide sufficient air flow rate in low flow situations.

The exhaust system is made of stainless steel and the catalytic converter is fitted in the silencer (absorption silencer). For exclusive use in competitive racing an optional performance silencer is offered as special equipment and it is possible to switch to the high performance “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 around the same as the class average (under 30 kg). The exact power and torque data are not yet fixed.

Chassis.

The chassis of the BMW G 450 X is a completely new development that uses selected high-quality components and materials. The years of GS model experience of BMW Motorrad flowed into 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 properties in terrain with ease of handling, great manoeuvrability and extreme tracking stability.

Full size image click HERE

Innovative frame concept.

The frame layout is based on the experiences of the development engineers, the know-how from competitive racing and attendant research and development work. The knowledge gained from earlier rally sport activities was also incorporated. The frame of the BMW G 450 X is an absolutely new development that differs in principle from all constructions of the competition.

In the main part 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 just 8.6 kg and is distinguished by excellent stiffness. The lower bow of the frame tubes runs directly from the swinging axle straight to the steering head. On the other hand, 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 now only needs to bear the weight of the rider. All in all this construction enables the optimum flow of force, requires minimum use of material, thus allowing a hitherto unrivalled ratio of rigidity to weight.
The 18-inch rear wheel is suspended in a robustly dimensioned two-arm swing arm made from aluminium square profiles which supports a directly linked Öhlins central suspension strut with a generous spring travel of 320mm. This high-technology element is variably adjustable in compression and rebound stroke damping as well as in the spring preload. The suspension of the 21-inch front wheel is undertaken by a 45 mm upside-down fork by Marzocchi that absorbs even the roughest bumps with a spring travel of 300mm and is also fully adjustable.

A powerful brake system with double-piston floating calliper from Brembo ensures the deceleration of the BMW G 450 X is safe and secure as well as fast. The front single brake disc has a diameter of 260 mm, the rear disc measures 220 mm. Given the intended function of this race-bred machine, ABS is not offered. 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 bashguard protection fitted as standard and that has already proved itself in racing. The motorcycle also has a double-butted Magura aluminium handlebar that guarantees optimum strength and ergonomics.

Full size image click HERE

Patented swing arm mount.

The real finesse in the chassis and a unique feature of the BMW G 450 X is the coaxial mount of the swing arm and countershaft. The swing arm pivot has been mounted through the hollow gearbox output so that there is no longer any change in length of the chain on compression and rebound over the entire spring travel. The chain tension remains constant independent of the compression position; the chain and sprockets are subject to less wear than in conventional applications. 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 countershaft the swing arm is 30 mm longer, without affecting the wheelbase.

The rear wheel remains more firmly in touch with the ground for longer, enhancing traction, and thus speed. A further benefit is a significantly greater length adjustment range of the rear wheel results which means different countershaft sprocket combinations can be used with the same chain with no problem. When a countershaft sprocket 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 sprocket in about 15minutes and, because of the much lower wear of the entire final drive, the sprocket needs to be replaced less often than traditional designs.

Design.

The BMW G 450 X fits the new G series family style enhanced by the dynamic “Flyline” along with the traditional BMW off-road family ‘beak’ over the front wheel, characteristic of all GS models. The look is sporting performance with a hint of aggression and a vibrant will to win. As with the G 650 Xchallenge, the G 450 X is finished in “racing white” with typical blue BMW highlights.

Technical Data.

Final technical data for the new BMW G 450 X has not yet been fixed. The maximum output is around 37 kW (50 PS) with a peak torque value of approximately 48 Nm. The overall weight with full tank is about 120 kg which means the BMW G 450 X is lighter than the current best weight values in this class. This value is all the more impressive because this is a vehicle with fuel injection, catalytic converter, electric starter and Euro III homologation that points the way to the future of the enduro sport. The exact geometrical data of the chassis is subject to the last fine tuning activities and will be made known at a later date.