MX TEST: KAWASAKI KX450F
“The riders can’t handle 450s. If everybody was James Stewart, we wouldn’t have this problem. The competition is bad because very few riders can ride the bike to its potential.” Those were the words of AMA Pro Racing’s Steve Whitelock at the Detroit Supercross. The riders he was talking about were the best racers in America; guys like Ivan Tedesco and Kyle Lewis.
Is it true? Is a 450 MXer too much bike for anyone in America whose name isn’t James Stewart or Ricky Carmichael? If the 450 we’re talking about is the 2007 Kawasaki KX450F, then he might have a point. We loved the 2007 KX; we loved the handling, we loved the suspension and we loved the motor. But we just couldn’t ride it. It was too fast. The motor hit hard and moved out. It was actually great fun on a practice track, but when you had to master the bike in the structure of an official race, we decided we had to go home and eat more Wheaties.
THAT WAS THEN …
For 2008 the Kawasaki is back with a few changes. But it doesn‘t have a giant governor or a big plug in the muffler. Kawasaki dealt with the motor’s gnarly power delivery exactly as you might expect: the crank mass and flywheel weight were increased. We learned the value of this a couple of months ago when we rode Destry Abbott’s KX/KLX hybrid. The bike started off as an electric-start KLX and then got the KX head, piston and cams. The crank mass and the ignition were still KLX, and made the machine into a real sweetheart of a bike. The 2008 KX doesn’t have nearly as much crank mass as the KLX, but more than the old KX. The ignition curve is new, but Kawasaki reports that this change was made for easier starting rather than a smoother power delivery. The crank is definitely new with a different shape and balance to reduce vibes. Here’s an interesting change: the engine spacers are 10mm wider to reduce the frame’s torsional rigidity. Torsional rigidity. Say that a few times. It sounds good, doesn‘t it?
Then there are the usual annual changes in the suspension. The fork valving is new and the insides have a low-friction Kashima coating for smoother action. The same is true for the rear shock. Spring rates are unchanged. All the remaining changes are aimed at improving reliability; things like a different connecting rod material, a bigger oil pump and reconfigured oil jets, which spray oil under the piston for cooling. There are also some minor changes in the shifting mechanism and at the pipe junction.
All of that adds up to a bike that really isn’t that new. It seems that all the manufacturers are taking a deep breath in 2008 before the next big cycle of changes. That can be a very good thing–at least it is in the case of the Kawasaki. The KX only got attention whre it needed attention.
ROOST FACTOR
All we remember about the 2007 model is its crazy motor. It was fast, fast, fast. A few of us noticed that it was green and had two wheels, but mostly that it was fast. If we could have used a remote-control bomb-squad robot for testing the new bike, we would have. Imagine our surprise. Not only could we ride the ‘08, but we could actually ride it fast. There were reports that a few riders actually opened the throttle all the way.
Don’t get us wrong, the 2008 KX still is fast. It hauls. We would still consider it the fastest of the 450s, at least the ones that we have ridden so far. We should point out that the 2007 KTM 450SX made more power on the dyno, but that didn’t translate into anything realistic on the track. The old KX was the real horsepower king and the new one will probably take over in its place. But it will be a kinder king. Whether it was the additional flywheel or something undisclosed in the ignition curve, the new bike is much easier to ride. The power starts early, but that wicked burst has been replaced with more of a even surge. As long as you pay attention to what your right wrist is up to, you can make the KX hook up and find traction.
Part of the formula is absolutely perfect carburetion. Kawasaki seems to have a secret that no one else can figure out. Even the Honda CRF450R has rich spots and lean spots throughout the rev range that are impossible to jet away. Not the Kawasaki. It doesn’t flame out, ever. Sure, you can stomp on the rear brake and stall it, but if you crack the throttle open at any rpm, the Kawasaki keeps going. It’s almost two-stroke-like in that regard.
If you have enough space, the KX will still show how much power it has. Open the throttle and it still out accelerates virtually [anything.] It does all of its work in the middle of the powerband. On top it revs out about like a Honda or Suzuki, but if you over-rev it, it falls off fairly quick with some pops and hiccups. But that’s what the shifter is for. The gear ratios, by the way, are much wider on the KX than on most 450s. If you ride GPs or even some desert races, you can probably leave the stock gearing in place. The KX will do almost 90mph on top and there are no real gaps between the gears. Realistically, you can ride an entire moto on most tracks with only second and third gears.
WHAT ABOUT THE TURNS?
The Kawasaki is decent in the turns. It’s more agile than a Yamaha but perhaps not as much as a Suzuki or Honda. For 2008, Kawasaki’s rear shock valving is just a little stiffer to keep the steering sharp. As far as we’re concerned, the change has no negative side effects. The bike turns and still goes perfectly straight when asked. It’s certainly a big bike. You know all those clichés about 450s that belie their weight? They don’t apply here. The KX weighs 232 pounds and it feels like it weighs 232 pounds. It’s a big bike and it suits big riders well. The space between the pegs, bars and seat is fairly spread out compared to a Yamaha. With the stiffer rear suspension this year, short riders can probably get away with running a little more than the traditional 100mm of sag. We’ve found that the Kawasaki isn’t particularly fussy about suspension settings. You set it up and let it go. That’s the mark of a well-balanced machine.
We love the fork. It works well for all of our test riders. It doesn’t dive excessively, yet it sucks up the little chop on the track that usually drives us crazy. Any fork can be made to handle big hits. But holes and square-edges, those are hard, and the Kawasaki makes them go away. We should also note that the “Diamond-like coating” on the fork tubes is apparently more than an advertising pitch. Last year, our KX450 got a lot of hard use and the fork seals never started leaking. We’ll credit that to the hard coating until we learn otherwise.
In the rear, the suspension is good. Like we said, it isn’t one of those bikes that has one good setting and 30,000 bad ones. If you want a stiffer ride in the back, you give it a few extra clicks without fear–the working range is fairly large. Pete Murray experimented with some setting to make the front end cut through turns a little sharper; he increased compression damping at both ends. The fork and the low-speed compression on the shock were turned clockwise two clicks and the high-speed compression on the shock went in one eighth of a turn. Most riders liked that setting, but it wasn’t something they had to have.
GREEN AND MEAN
Frankly, there’s no real reason that the Kawasaki should take a back seat to any 450 this year as far as performance goes. We still have reservations about the quality on some fronts, though. Last year the KX clutch would start slipping after just a few rides. This year there aren’t any clutch changes. The bars are aluminum but not oversize like those of the Yamaha, Suzuki and KTM. Our seat held up during our first few rides, but the foam has a reputation for breaking down. And the biggest of our small snivels is the noise factor. The KX is loud. It might pass a sound test in neutral because the ignition is retarded whenever the bike isn’t in gear. But on the track it’s an ear splitter.
Still, if you gather up the handful of things that we don’t like about the Kawasaki, they don’t add up to much. One blip of the throttle can cancel it all out and make you fall in love. Power is the bottom line in the 450 class. If it’s rideable, you have a winner. And this year the Kawasaki is rideable.
UPPERS
* Fast
* We can hold one this year
* Turns well and is stable
* Excellent suspension
* “Diamond-like” fork coating seems to work
DOWNERS
* Small 7/8th bars
* Wobbly rubber bar mounts
* Seat foam breaks down
* Clutch slips quickly
* Loud
JUST THE FACTS
* Running weight, no fuel…232 lb.
* Suggested retail price…$6999
* Distributor/manufacturer:
Kawasaki Motor Corp.,
(949) 770-0400
https://www.kawasaki.com/Home/Home.aspx
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