CW ARCHIVES: Kawasaki KLX450R vs. Yamaha WR450F - COMPARISON TEST

Evidently, Kawasaki has some calendar issues. The company introduced its all-new KLX450R to the press in late March, calling the bike a 2008 model, but then had units in showrooms just a few weeks later. In my book, that makes it a 2007 model. I guess I don’t quite understand marketing and sales. Not that it matters, because my job is to understand motorcycles.

As for this new KLX, it is derived directly from Kawasaki's KX450F motocrosser, the green bike on which James Stewart dominates the AMA Supercross series. That's a common method of developing enduro bikes, and the Yamaha WR450F likewise is a direct offshoot of the YZ450F motocrosser, as it has been since its introduction in 1998.

So, what we have here are an all-new KLX450R and a completely reworked WR450F. What better, then, than a head-to-head matchup between the two?

To help us determine a winner, we rode these off-road-only machines in the Arizona desert, hammered them in Baja California, climbed up to the peaks of the Piute Mountains, ran them around our secret enduro test course and topped it all with a day in the openness of the Mojave desert. In other words, we subjected them to all manner of off-road riding conditions, logging more than 800 miles on each one.

That number was easy to calculate because both bikes have digital odometers and dual tripmeters. They also are equipped with clocks, and the WR even has an adjustable enduro timer. Both have kickstands, head- and taillights, pushbutton starting, larger fuel tanks with Reserve, radiator catch tanks, 18-inch rear wheels, skidplates, side-entry airboxes and adventure written all over. And obviously, the motors and suspensions on both have been tuned specifically for off-road use.

In fact, if you were to compare either of these bikes’ suspensions to those of their pure-bred motocross siblings, you’d be shocked at the differences. The forks and shocks on these two were calibrated not with triple-jump landings in mind but rather to help them comfortably soak up all kinds of off-road terrain–little bumps, big rocks, deep ruts, high-speed whoop-de-dos and anything else Mother Earth might throw at them.

Though both bikes use very similar KYB suspension at both ends, the Kawasaki got the better fork components. It has the same air-oil separation system used on the KX450F MXer minus the Diamond Like Coating (DLC). Yamaha chose a cheaper route by not giving the WR the same higher-end internals found in the YZ-F forks. Maybe that explains the $100 difference in these bikes’ retail prices: The WR is $7199 and the KLX is $7299.

When it comes to overall handling, though, both bikes are dream rides compared to any previous off-roader, including the highly touted KTM 450 EXC. Though the Yamaha is superb in this department, the KLX gets the gold medal thanks to a super-plush ride and a perfect balance that bless the green bike with a magical feel.

Some of the credit for that excellent handling is owed to these bikes’ aluminum frames, and we have two types here: The Yamaha uses a backbone style and the Kawasaki has a twin-spar design. Both are claimed to help provide better mass-centralization that allows their chassis to possess nimbleness more like that of a two-stroke enduro. Both bikes have quick, easy steering, but the WR’s is a bit more precise than the KLX’s.

Swapping the stock front tires for Dunlop’s new 742FAs closed the steering discrepancy ever so slightly, but the WR still came out on top in that category. And since we were prying on new rubber up front, we also installed Dunlop’s 952 off-road knobs on the rears. They’re made with a harder compound that provides more tread life than the stockers.

These 450cc engines are fully capable of burning off that tread in no time flat. Kawasaki is still a newbie in this category, as 2008 will be just the third year for its competition-oriented, 449cc liquid-cooled four-stroke. To build the KLX motor, Kawasaki took the KX-F engine, doubled the flywheel weight, added a low-boy header pipe, revised the cam lift and timing, corked it up to meet emissions and dropped in a wide-ratio transmission. The result is a super-smooth, torque-monster of a motor. Its characteristics are similar to those of Honda’s CRF450X: electric-feeling but freer-flowing with more bottom-end punch. Due to the latest emissions regulations, the Kawi’s 40mm Keihin FCR carburetor is not adjustable from the outside and the needle is in a fixed position. Despite that, our test bike ran great everywhere, even at higher altitudes.

Can’t say the same for the Yamaha, which got rich and ran rough at altitude, killing some of the power when we were in the mountains. That’s surprising, because the WR was equipped with what’s called “closed-course” settings that include revised jetting. The closed-course mods involve removing the throttle stop and smallest muffler baffle, cutting the gray wire in the ignition harness and installing different jetting that’s available through Yamaha’s GYT-R accessory department. As this upgrade’s name implies, however, making these modifications also renders the WR illegal for use on public lands.

When the WR’s 449cc liquid-cooled four-stroke is left stone-stock, it runs like a bike with much less displacement; but when it’s uncorked, it rips. The low-end power is crisp, the midrange is stout and the top-end is impressive, making the WR noticeably faster than the KLX. Though the Yamaha still has a dry-sump oiling system, the oil reservoir has been relocated into the engine cases for better mass-centralization. The cylinder angle was made more upright, and the crankshaft and balancer now have a 50/50 ratio that yields smoother running. Revised cams, carburetion, intake porting and exhaust specs help boost low-end and midrange power.

When it comes down to fit and finish, this comparo is a toss-up. The plastic bodywork is stylish on both, with the Kawasaki having the better LED taillight integrated into the rear fender. The WR’s taillight is an improvement over last year’s but still looks like an afterthought. And speaking of afterthoughts, the KLX’s headlight points way too high, even when cranked downward as far as the adjuster will allow. The Yamaha still has the best headlight for night riding even though it has less output than last year.

In the saddle or standing on the pegs, the WR has a slimmer profile and is a bit roomier than the KLX. The Kawasaki is not scrunched by any means, but its ergonomics are just a little tighter. Both bikes have the same claimed fuel capacity of 2.1 gallons, but on average, the Kawasaki will go about 15 miles farther than the Yamaha. About the time the WR runs out of gas altogether, the Kawasaki is just hitting Reserve.

So, we have here a Yamaha that’s set up as a trailbike and works best in tighter, technical terrain like found in Eastern enduros. The Kawasaki, meanwhile, performs better in an open environment with higher speeds in mind such as desert riding and Grand Prix racing in the Southwest. Uncorked, the WR’s engine will blow the doors off the KLX, but in legal form, the Kawasaki leaves the Yamaha in the dust–literally. Plus, the KLX handles better overall and is more forgiving of rider error.

Picking a winner between these two was tough, but after taking all the meaningful factors into consideration, we chose the Kawasaki. It kicks butt in the desert, can keep up with the WR in the technical stuff and is more rider-friendly on all kinds of trails. And we especially like the fact that it doesn’t require you to horse around with any emissions equipment. You just buy it and ride it.

Team Green takes this one.