Thunder In Oklahoma
THUNDER IN OKLAHOMA
CW COMPARISON
The storm of big-bore four-strokes has arrived
RAYN DUDEK
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FORGET ABOUT TWISTERS. THE CYCLE WORLD TEST CREW blew into Oklahoma with a sextet of spanking-new rumble-makers, the latest crop of lightning-fast 450cc Thumpers. Our goal? Get out of California and land on some choice dirt in hopes of finding the best motocross bike to hit American soil in 2006.
With most of upper North America frozen over for the winter,
Stillwater, Oklahoma, was the place to be. That’s the home of Guy Cooper, our guest-tester for a few days, and site of Cooperland, the motocross track he founded, full of lush dirt, hard-pack, loam, small hills, big jumps and a variety of turns. No better place for a Whacking Great Thump-Off.
With a new bike in the mix and heavy updates to the veterans of the class, stakes were high, so to even the playing field, we stuck Dunlop 756s on all the bikes. With that, we were ready for battle.
changes to the `06 model of the others? We start with last year's Open class king and a CWTen Best win• ner four years running: Honda's CRF45OR. Since its introduction in 2002, the CRF has been the benchmark among the 450cc motocrossers. But would minor be enough to keep the bike ahead
Even though they already had an award-winning MX bike, Honda's R&D guys haven't been sitting on their hands. They tweaked the 450R in a few areas, such as tilting the engine slightly forward, lowering the crankshaft 5mm and dropping the radiators 5mm, the idea being to lower the overall center of gravity. The net result is that the front end now feels more firmly planted, with improved steering and better in-corner stability. The suspension package is plush, just like it was last year, and delivers a forgiving, predict able ride. Overall, the CRF45OR is light, agile and super easy to control.
As for the engine, it has remained the same as in `05-and that's okay, because the 449cc powerplant was touted as the best in class last year. It's tractable, smooth and, as always, ultra-fast.
HONDA
CRF450R
$6899
Thanks to that fantastic engine and a great chassis, the CRF is a well-rounded bike that boosts rider confidence, even on the first lap around the track. So, once again, the CRF45OR is the closest thing to a works bike you can buy off the showroom floor. But is that what the average rider needs?
Moving in alphabetical order, next in line is the Husqvarna TC450. Though this Italian-built bike with a Swedish name is no Honda, it has improved by leaps and bounds over its `05 predecessor via new suspen sion, reduced weight and improved engine performance.
Most noticeable of these upgrades is the completely new suspension package. An Öhlins shock replaces the Sachs unit on last year’s bike, making for a huge improvement in rear-end stability and tracking. The fork is still the same basic Marzocchi unit but heavily upgraded with new internals that include sealed damper cartridges. The tube diameter was increased from 45mm to 50mm for less front-end flex and more-precise steering.
Removing the ’05 TC450’s electric starter brought about the ’06 bike’s second-best improvement, reducing overall weight by 8 pounds. Despite that, the TC still is the heaviest of these six machines and needs to lose another 8 pounds to be on par with the others. A new kicker system makes kick-starting pretty easy, but if you just gotta have the luxury of an e-button, an optional electric-start kit is available. As for engine upgrades, the intake and exhaust valves are bigger this year, and the combustion chamber, piston, intake cams and intake and exhaust manifolds all are new.
What does all this mean? Smoother power than on last year’s bike, with tractable horses you can put down on the track. What the motor lacks in abrupt punch it makes up for in controllable power, making it a good choice for slippery, blue-groove tracks.
HUSQVARNA
TC450
$6599
If the TC sounds like a good package, it's because that's what it is. It's still a little behind the front-runners in overall handling, but give it time; the factory is working hard to make Husqvarna a household name once again.
The late entry of this group is a bike we've all been waiting for: the all-new Kawasaki KX45OF. It arrives just two years shy of a decade after the start of the four-stroke revolution in moto cross. But despite showing up for class a little late, the green beast is more than capable of battling with the best in hopes of becoming the new class leader.
"Beast" is an appropriate description for this bike, espe cially when referring to its growling, spine-tingling, 449cc engine, a motor that begs to be ridden hard. The all-new, four-valve, dohc Thumper delivers aggressive punch with responsive throttle control much like that of a two-stroke; it's fast and fun and has a broad range of power similar to that of the RM-Z.
Cradling that quick, snappy engine is a twin-spar alumi num frame-comparable to those on the Honda and Suzuki 450s-working with an aluminum swingarm and Uni-Trak rear linkage system. The KYB suspension package is new, featuring a fork that incorporates that company's AOS sys tem that keeps air and oil in separate chambers for consisten damping during long motos. The shock is updated with a larger compression-adjuster port that allows the rider to more easily feel the differences in damping after adjusting the clickers.
Overall, the KX's handling is on par with its competition, offering a competent, predictable ride that borders on being harsh. The riding position is comfortable but large and open with a seat that feels wider than those on the other 450s. That's not a bad thing, since it allows riders on both sides of the size scale to fit comfortably.
KAWASAKI
KX450F
$6799
The KX45OF is a solid pack age that definitely is made to win races-a point already proven by James Stewart.
Next on the list of big four-stroke MXers is the KTM 450 SX. It arrives in 2006 with only a few mechani cal changes from the `05 model, but it does manage to top the charts in terms of BNG (Bold New Graphics). The frame color was changed to black, along with the fork and rims, and the fork guards and shock spring are done up in KTM's signature orange. -
In the engine, a stiffer crankshaft and sintered steel valve guides both are changes meant to improve durability. Throttle response was sharpened with a new FCR41 carbu retor, but performance-wise, the engine is on the lazy side and lacks somewhat in top end grunt. The motor is still plenty fast, though, and its easy flow of power allows you to ride longer motos with less fatigue.
KTM
450 SX
$6998
If only the chassis were so forgiving. A new, stiffer swing arm is claimed to help rear-end stability, while the fork was recalibrated for `06 and has new bushings for less stiction. But even though the orange 450 handles better than it did last year, it still comes up just a bit short in that department compared to the Japanese bikes.
As for riding position, the KTM's is different than what you'll find on the other bikes. It has a unique feel and is the narrowest by far but is not at all uncomfortable; it simply takes a little getting used to. There is, however, one signifi cant flaw: The radiator shroud has a sizable hole where it attaches to the gas tank, and if the rider wears knee braces, the shape and depth of that hole can hook the brace and lock the rider's leg to the bike. Not good.
Nevertheless, the KTM 450 SX is still a great bike; prob L~'~ is, it's quickly becoming outdated by the new equipment from Japan. We look forward to seeing an all-new 450 SX in 2007.
Next comes the Suzuki RM-Z450, now in its second year of glory. Last year, the RM-Z proved itself by almost knocking the Honda 450 off its pedestal, missing victory by just a hair. In the ensuing year, Suzuki has had plenty of time to figure things out, make updates and come back swinging once again. The company's goal for `06 was to make the 450 even easier to ride while not only keeping every bit of its `05 performance but also add ing some more.
To that end, the engine got a few tweaks that included a• redesigned cylinder head, new cams, recalibrated carbure tor settings and revised ignition mapping. The rear sprocket dropped a tooth from a 49 to 48, marginally widening the gaps between gears and allowing a faster top speed.
SUZUKI
RM-Z450
$6599
) Out on the track, the RM-Z's power can best be described as average. The engine is respon sive, with lots of snap, and because its torque is bountiffil, it pulls hard. But overall, it doesn't stand out in any way other than perhaps needing a little more juice on top.
As for handling, the RM-Z450 does stand out, and not just in pos itive ways. If it were the only bike in this class, you'd praise it for handling so well; but after riding them all, you'd say that the Suzuki is good but not great. The suspen sion is predictable, though on rough straights, the RM-Z tends to be a little busy and the fork could use more-progressive damping.
Chassis-wise, the RM-Z feels the smallest, which is nice in a number of ways. It makes the bike easy to maneuver and easily accommodates smaller riders. The riding position can be a little tight for extremely tall people, though it's nothing that can't be easily overcome.
When it comes to steering, the RM-Z once again is the class of this class, able to slice around any turn quickly and accurately.
Just point it where you want to go, and the RM-Z will dive around the corner better than any other 450 here.
Last alphabetically but certainly not in rankings is Yamaha's YZ45OF, the descendant of the bike indi rectly responsible for this four-strok revival in the first place. Not only is Yamaha's four-stroke MXer nothing like the original 1998 YZ400F, it's even a lot different than last year's 450. Can you say revamp? This year, the YZ got the re-do it needed-and deserved.
First and foremost of the changes is a new backbone-style frame built with cast-, extrudedand forged-aluminum pieces. The engine has been placed lower and nearer the center of the bike for improved mass centralization, complemented by a heavily revised Kayaba suspension package. The fork uses what is called a Speed Sensitive System (S3 for short) that varies the damping according to piston speed.
On the track, the fork works perfectly, soaking up all the small bumps without blowing through on the big hits. The rear end works just as well, with an all-new shock that incorporates a larger rod and fluid reservoir. And in a first for production bikes, the shock spring is titanium, claimed to have the same durability as steel while being 30 percent lighter.
This new chassis has improved the bike’s comfort quotient, as well, and does away with the “stink-bug” rear end of the previous model; the YZ now has a flat seat profile that allows the rider to move around more easily. The handlebar is low compared to those on the other 450s but seems able to accommodate riders of all sizes.
Down in the engine compartment, Yamaha got it right.
The YZ-F hammers out tons of smooth, usable power that is strong everywhere-bottom, midrange and top end. And thanks to a new five-speed transmission, there’s an ideal gear for every corner, every on-track situation.
So, what’s the scoop with these six 450cc Thumpers? Which one rules?
Well, ride any one of them and you’ll know for sure that we live in a great time for motorcycling. And when you get right down to it, there are no losers here; all of these 450s new level of confidence. are exceptional. All are very similar, all are great fun and all can give just about any rider a
YAMAHA
YZ450F
$6899
But in the end, just one of these 450s does everything a tiny bit better than the rest, enough so to have received the most first-place votes by our cast of test riders. And for the fifth straight year, the Honda CRF450R is the bike of choice. With its composed handling, precise steering, excellent comfort level and mega-motor, it’s the bike to beat. Just add gas and go chase your next trophy.
Second place goes to Yamaha’s YZ450F, a bike that is unmatched in versatility, raw power and sophisticated suspension. Had it gotten just one more first-place vote, it would have tied the Honda for the top spot on the podium.
Ending up in a third-place tie were the Suzuki and Kawasaki. Hmm. Funny how that turned out, seeing as how the two companies used to have an alliance. And even though these two bikes are not the same, they still behave like siblings.
That leaves the two European bikes to take up the final spots. In most ways, it’s a toss-up between the two, and which one finishes where is really not all that significant for the purposes of this test. We set out to find the winner, and that mission has been accomplished. As we stated earlier, they’re all terrific motorcycles; it’s just that some are marginally better than others.
Guy Cooper probably summed it up best: “Out of the crate, these bikes are set up better than any factory bike I’ve ever raced. Times have changed, and for the better.” □
