BMW G450X Project, Part 1

Apr. 28, 2010 By Dan Paris

When BMW announced they were going off-road racing with their innovative new 450, the world took notice. The G450X, if you haven’t seen one yet, are unusual to say the least. The fuel-injected engine, made by Kymco for BMW, is canted forward in the stainless-steel trellis-style frame. The swingarm pivot and the countershaft sprocket share the same axis, eliminating chain tension changes as the rear suspension cycles. The gas tank is where the airbox is on any other dirt bike, while the airbox is up under the ‘tank’ area.

You can go on an on about little details unusual to this machine, but the bottom line is BMW took on too much, too soon. Bad press tempered BMW’s racing success, like Juha Salminen finishing second in the FIM World Enduro Series, when David Knight suddenly quit the BMW team last season. Up in the Great White North, Guy Giroux rode his BMW Canada 450X to fourth overall in the Royal Distributing Canadian Enduro Championship and third at the Montreal Endurocross in front of 60,000 people. So obviously the bike can work.

We were lucky enough to score the exact same machine Giroux raced at the Montreal Endurocross as a long-term project bike, minus a few of the factory items. We dove into this project with an open mind, our goals being to race and ride the BMW every chance we get, learn its idiosyncrasies and improve upon its overall performance.

Our first date with the BMW was at an arenacross track, where Canadian Pro Jason Michael cut some fast lap times after an unusually large amount of adaptation time. BMW Canada’s Guy Giroux, shown here leading Husaberg’s Shane Cuthbertson and KTM’s Jason Schrage at Montreal, did plenty of R&D work during the 2009 season. He used a Honda CRF450R fork and triple clamp with 24mm offset to improve rigidity and steering precision over the stock Marzocchi set-up. The rear Ohlins shock was re-valved in an effort to eliminate being too soft and blowing through travel or being too heavily valved and harsh. With no suspension linkage, this was a challenge. In fact, once the shock valving was finally set optimally Giroux says shock oil overheating became an issue. Photo: Angie Parker

 

Re-valved and re-sprung Marzocchi forks were reinstalled on our BMW, along with the very restrictive stock muffler. During the Enduro Championship Giroux raced with a titanium Akrapovic system. We’ll deal with that in the next instalment of this project. Anyway, getting back to boingers, Giroux’s Montreal Endurocross rear suspension settings worked pretty well at our Arenacross track. The BMW is slim and aggressive looking but has weird ergonomics. The saddle is as hard as a rock, but it offers a flat seating area and is well shaped. The footpegs feel a little too far forward, while the front end feels too low regardless of handlebar position, handlebar clamp position or suspension sag adjustments. According to Giroux the resulting ‘stinkbug’ feel of the BMW is something you get used to. So far, we haven’t.

 

The BMW is sold as a legit dual sport bike, despite being a hard-core dirt bike. Removing the dual sport gear from the BMW, except for the headlight, saved us 6.90 pounds and took us about 6.90 minutes. It’s cool that you can lose that much weight by simply unplugging a few things, but it’s also cool that BMW managed to make this motorcycle street legal with such a small addition in weight.
Fill’er up! The BMW never fails to draw a crowd when you fill up the airbox with gas through the hole in the seat. The tank is fairly small, netting only about a 30-mile range under racing conditions. There is a low fuel light to tell you when you need to start sweating.

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The airbox is accessed by taking off the right side radiator shroud, which is held on with way too many little bolts and washers. The Twin Air foam filter is then removed for cleaning like a giant slice of toast.

 

A great big single radiator, complete with a cooling fan, hangs in front of the engine. It works fine but could use an aluminum guard to protect it from damage.

 

Here’s another look at the gas tank, the re-valved direct link Ohlins Shock and the airbox.

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Here’s a good shot of the front sprocket/swingarm pivot arrangement. BMW says you can change the front sprocket in a few minutes by pulling the swingarm back. We’re not so sure…

 

Our second outing with the BMW was a cold, slippery trail ride. It was hard to tell much about the bike under those conditions, but it did get an amazing amount of traction. It certainly wasn’t because of the tires, which are those sucky FIM-Enduro spec short knob jobs that European off-road bikes tend to come with. So maybe that big long swingarm and front sprocket arrangement does work?

 

Fredette Racing Products http://www.frpoffroad.com/index.htm set us up with a set of tires to go ice racing. In case you wondered, that’s why the tires were wrapped with cardboard in the front sprocket photo. It was an effort to keep the studs sharp while pushing the bike around in the garage.

Bavarian Buzzsaw. Here’s a closer look at the business end of the BMW with the Fredette studded tire.

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The BMW worked ‘ok’ on the ice. With the giant muffler, which is complete with a catalytic converter, the powerband flattened early and top end power was not competitive with all 450F motocross bikes we shared the ice with. There are two positions for EFI mapping; an EPA-friendly low-setting claimed to be 40.2 Hp and an ‘off-road’ setting of 50.9 Hp. With the stock muffler you aren’t supposed to run the off-road setting, for fear of damaging the catalytic converter. We did it anyway and the bike ran just fine, but was still slower than the other 450s out there. We were also frustrated by the height of the bike on oval and road-style ice courses, but loved the low-end torque and powerful brakes. We can also report in two months of constantly running wide open, under a huge load on the ice, the BMW engine, transmission and clutch never skipped a beat.

 

Razor’s Edge Ice Racing Products supplied us with some heavy duty tire covers. They fit and look great! Razor’s Edge can be reached at 780-539-6587. BMW supplied us with a very solid aluminum skid plate from their parts catalogue that installed easily. Despite having a tall seat height the BMW doesn’t have as much ground clearance as most off-road race bikes, so this is an absolute necessity.

 

An early spring thaw let us take the bike for some proper trail rides. The modified suspension that worked well indoors has had us spinning clickers like madmen to make it more compliant for the woods, with mixed results. We also found the gear spread of the transmission is too great, with big gaps between 1st, 2nd and 3rd that are annoying. Future plans for the Beemer include better tires, a less restrictive effective exhaust system, hand guards and assorted trail armor, gearing changes and further suspension tuning. We’ll address those areas in part-two!
Photo: Arley Orosz


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