Off-road worthy motorcycles from MO’s past seem to be pretty popular Church items lately, so we’ll continue the theme again this week with a dirtbike from BMW. No, not the R1200GS, but a real dirtbike, the 2009 BMW G450X. In a time when BMW was trying to reinvent itself to attract new riders, the G450X presented something radically different than the comfy touring bikes many younger riders pictured their parents – or even grandparents – riding. Ultimately, the G450X had a short shelf life, but the guts to continually reinvent itself and enter new motorcycling categories has resulted in products like the RnineT and the S1000 lineup. For that we partially have the G450X to thank. Here’s contributor Jeff Buchanan with his take on BMW’s dirtbike.
Jun. 13, 2008
Photos by BMW
What better way for BMW – an established marque that is rapidly reshaping itself – to leave its longtime persona of gentlemanly conservatism in the dust than to build a serious dirt bike? The all new G450X is the latest in a continuing line of completely fresh, clean-sheet machines to emerge from the Munich-based manufacturer in a radical detour that reinforces the notion (to borrow a very tired cliché): this isn’t your father’s BMW.
For anyone paying attention, BMW Motorrad is aggressively redefining itself. In place of flashy marketing campaigns shallowly trumpeting a new direction, the German brand is letting its two-wheel product speak for itself, unveiling one new machine after another. Their latest, the G450X, represents a bold move into semi-uncharted territory.
Although BMW virtually invented the Adventure class with the iconic, go-anywhere GS, and proved they weren’t afraid of getting dirty with multiple wins in the grueling Paris-Dakar Rally, this new bike represents BMW’s first serious gambit into the tumultuous off-road arena for the consumer. I see now that the enigmatic HP2 was merely an aperitif, hinting at the company’s more serious dirt-oriented aspirations. The G450X, a wholly fresh creation boasting some innovative design cues wedded to BMW’s signature sophisticated engineering, was rolled out last week in Marbella, Spain for the world press.
Quite simply, the “G” designation of the 450 denotes a new Generation motorcycle for BMW. The nascent machine borrows some prominent internal technical DNA from the K-series sportbike, its aggressive, all-business off-road persona wrapped up handsomely in BMW’s striking racing livery of blue accents on bright white. The bike gets a “beak” front fender – made popular by its GS brethren – with sparse bodywork shaped by sharp angles that render an arrow-like wedge look. Razor-thin and compact, the 450 is a dynamic-looking machine.
Aesthetically, the most prominent design element of the 450 is the tubular frame. Constructed of twin cross tubes of stainless steel mated to forged union points, the chassis design foregoes the traditional undercarriage that cradles the motor. Instead, the main tubes run at a 45-degree angle from the beefy steering stem directly to the swingarm pivot. It is rudimentary engineering, designed to transmit the intense forces absorbed through the front forks to the machine’s center of mass via the most direct route. By comparison, a traditional under-slung frame carries the energy of impact through a somewhat circuitous route. The 450X’s unique chassis design requires less tubing than a conventional frame, resulting in an extremely light unit that nonetheless delivers exceptional rigidity. Replacing the natural protection afforded by conventional under-slung chassis tubes, the G450X is equipped with an ultra heavy-duty bash plate that is mounted in shock-absorbing rubber.
That heavy-duty skid plate protects a liquid-cooled 449cc single-cylinder DOHC 4-stroke motor. Developed in-house, the powerplant borrows technology from BMW’s “K” bike in the form of a short-stroke (59.6mm) combined with a compact 4-valve head. Electronic fuel injection feeds the engine through a dual throttle valve. Crankshaft and connecting rod are roller bearing-mounted. A forged lightweight 2-ring piston drives the combustion process.
As a street-legal platform, the G450X was designed to comply with the exceedingly strict European emissions standards. However, U.S. recipients – under a different emission code – will benefit from the new bike being imported with an electrical “plug” that boosts horsepower significantly, adding 11 ponies to the European model, bringing output up to a solid 51 hp. In stock Euro mode the bike is no slouch, pumping out decent low-end, mid-range and top-end. However, the additional (U.S.) power is significant and gets spread out fairly evenly over the entire powerband, really showing itself on the top end when screaming the 450cc single in the upper rpm range. The importing transformation (which is actually about a two-minute procedure that involves removing a side panel and plugging the connector loop into place) helps to smooth out the engine at idle and low rpm.
In a unique configuration, the cable-operated small-diameter multi-disc clutch sits directly on the crankshaft, the layout contributing to the 450’s short engine length. An intermediate shaft transfers power to the gearbox, which means the G450X’s crankshaft rotates backwards. The compactness of the engine allowed it to be rotated forward a full 30-degrees to help shift more weight onto the front tire for better bite. Also, tilting the engine in the chassis created enough room for the air intake duct to come in vertically from above in a relatively straight configuration for optimum performance. The lack of traditional chassis down-tubes coming off the steering stem allows for a one-piece, large-capacity radiator. The lightweight unit is equipped with a fan to help draw air through the cooling webs at low speeds.
Perhaps the single most impressive design element of the G450X is the exclusive implementation of a coaxial swingarm pivot/countershaft. A hollow countershaft serves as the swingarm pivot bolt hole, allowing the countershaft sprocket to rotate around the swingarm pivot point. This completely eliminates the need to adjust the chain to accommodate the wild variations in tension due to 12 inches of rear wheel travel. It’s a surprisingly simple solution to a problem that has been the bane of long-travel suspension since its introduction over 35 years ago. It’s ironic that BMW would be the first manufacturer (not counting start-up MotoCzysz) to implement this ingenious design.
An added bonus of the coaxial design, which translates into chain tension remaining constant regardless of rear wheel travel, is that the stresses on the countershaft and transmission are greatly reduced. Removing this variance will undoubtedly prolong chain and sprocket life in addition to removing concerns over proper chain adjustment to accommodate the full arc of travel. The downside of this arrangement is that you have to remove the swingarm to change sprockets. This was addressed with an economical design that facilitates swingarm removal, reducing the procedure – once mastered – to a 15-minute job, according to BMW techs).
This coaxial design element, as well as the crankshaft-mounted clutch, saves an enormous amount of space and results in a very short motor. This allows for a longer swingarm to be used while still keeping the G450X to a 58-inch wheelbase. The advantage of a longer swingarm – in this case, a cast aluminum dual-sided heavy-duty unit – delivers an added element of stability, especially when the rear suspension is fully compressed. The rear axle slots in the swingarm are exceptionally long and provide a healthy allotment of movement, allowing for a variety of sprocket combinations to be tried without having to add or remove chain links.
Swinging a leg over the G450X and settling into the seat 37.6-inches above ground, the first thing that comes to mind is that the bike is extremely narrow. The single-piece radiator contributes to this, but also it’s the result of BMW engineers – intent on keeping the 450 X’s center of gravity low – finding a more appropriate location for the 8-liter fuel cell. It’s situated directly under the rider with the filler neck located in the rear portion of the seat, with the filler cap neatly receded just below the surface. There is an optional low seat for riders with a shorter in-seam, although there’s a price to be exacted on the bum; the cushioning is just one notch up from a 2×4. The G450X technical information sheet we received boasts a dry weight of 245 pounds. Naturally, we’ll want to weigh one ourselves for confirmation, but sitting astride the feathery light X it’s apparent that we won’t be blowing out our bathroom scale at home when we do.
Tapered Magura handlebar and levers are top-shelf components and contribute to the G450’s sanitary appearance. Handlebar clamps are designed to work in several different configurations on the triple clamp, affecting bar placement to accommodate rider preference and riding style. The electric starter automatically activates a decompression function that works through centrifugal force to reduce the power needed to crank the engine, thus preserving battery power and extending starter life. The machines presented to the press in Spain were equipped with aftermarket Akrapovic competition pipes. The stocker is considerably quieter and weighs a few extra pounds yet still manages to deliver respectable power. However, since most off-roaders usually immediately trade-up to an aftermarket pipe, it was just as well to experience the G450X with the extra muscle and appealing exhaust note afforded by a free-flowing exhaust system.
Once the engine was warm I trailed a bunch of European journalists from the hotel in the Marbella foothills two kilometers down through town to a motocross park (imagine that in America). From there we headed off onto various enduro routes laid out over the surrounding mountains, ranging from tight, rock-infested trails to washboard fire roads to technical sections.
For suspension BMW called on industry leader Ohlins to provide fully adjustable damping and rebound duties on the rear. The shock is mounted directly to the frame and swingarm without the use of a rising-rate linkage, delivering 12.6-inches of rear wheel travel. On the front the G450X is graced with a 45mm fully adjustable upside-down Marzocchi telescopic fork that renders 11.8-inches of travel. In stock settings the suspension provided a compliant ride over a wide variety of terrain, plush enough to absorb the small hits at speed yet progressive enough to swallow the more gnarly gaps in the trail and those scary diagonal rain ditches that seem to come out of nowhere. I nailed a few of those at speed and the BMW responded with real aplomb, remaining composed, never getting sideways or threatening me with a rude ejection.
The BMW’s light weight afforded confidence in extreme slow going where constant dabbing is the order of the day. In these tricky sections the 450’s low-end torque allowed attention to be paid to the terrain instead of playing with rpm. Feathering the clutch requires just one finger and is more of a thought than physical action. On fire roads the G450X behaved well, managing to hook up and find traction in even the driest, most slippery of conditions. The engine gains revs relatively quickly yet manages to accommodate a number of riding styles, from the rider who prefers lugging the motor and relying on bottom end to get through a section, to the pro who prefers to keep the thing singing in high revs. I’m somewhere in between, running in a gear high everywhere and using the old-school 2-stroke style of fanning the clutch to get the revs up. In all applications the motor is impressive.
The transmission is a constant-mesh 5-speed, rendering positive gear changes with or without the clutch. Ratios are spaced out nicely, allowing the rider to use each gear in turn, letting the motor build, as opposed to some motorcycles where a gear change is barely noticeable. The tranny is wonderfully forgiving, allowing you to get sloppy with shifts and not worry about coming up with a false neutral. For extreme slow going, a change in countershaft sprockets is going to be warranted to avoid frying the clutch.
Being Europe, we were treated to a Chrono (timed) dirt course as part of the traditional competitive enduro “special tests.” In the closed-course discipline, the G450X exhibited excellent handling manners, the bike going right where it was pointed with the front wheel tracking solidly, whether in berms or flat, loose, slippery corners. Power came on with a snappy resolve, the engine able to go in a gear high and with a quick slip of the clutch, power itself out.
One finger is all that’s needed on the front Brembo binder, a single 260mm floating disc grabbed by a 2-piston caliper. The front brake is grabby at first and takes a little getting used to. The rear brake, also a Brembo, utilizes a 220mm single disc mated to a single-piston caliper. Feel is somewhat progressive, with a decent level of predictable stopping power before lock-up. On the single-track trails the rear brake could be used to help steer, backing the rear end into tight turns to help square off the corner.
Engineers focused on ease of maintenance with regard to elements like the oil filter, which is easily accessed from the left side of the engine. The air filter, which is located under the right side radiator cowling, is a clever slide-out drawer configuration to make cleaning and/or replacing an easy operation (a welcome trait, especially in competition). The 450’s 1-liter engine oil capacity is easily checked through a glass inspection window.
BMW was certainly aiming for the fence when they embarked on this enduro effort. As the German giant has proven over the years, it doesn’t do things in half measures. Without question, the G450X is poised to take on the category’s leaders, possessing enough promise to render some surprises on the results page in its first full year of competition. However, it wouldn’t be a BMW if it weren’t designed for a wide range of rider ability. In addition to being a serious mount for the professional off-road racer, the G450X is well suited to the mid-level rider and tame enough for the semi-beginner.
The bike is imbued with some impressive, practical, and innovative design features, which augment a very capable package, whether you’re chasing points in a championship or merely heading into the mountains for a little fun. The BMW G450X is scheduled to make landfall Stateside in the fall.
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