2010 Kawasaki KX450F First Impression

Ah, there’s nothing like the smell of new bike in the morning. Kawasaki introduced the new and improved 2010 KX450F to the press yesterday at Pala Raceway in Southern California. With the release of the all-new fuel-injected KX450F last year, the 2010 only received a handful of moderate revisions – which is good news to us since we were plenty happy with our shootout winning ’09 KX.

Revisions that were made to the mighty Kawi focused on creating a slightly more aggressive overall package with revised suspension and a bigger hit from the motor. The concept of a KX450F with “more power” seemed a little scary to us at first, especially considering the robust and instant power of the ’09. But we’re happy to report that the big green machine still puts out loads of smooth, polished power in a civilized way.

While it’s certainly capable of being arm-yanking, the KX’s big torque pours on smoothly and power makes it all the way to the ground. The incredibly crisp fuel-injection still delivers power instantly, with no lag whatsoever between the throttle and the rear wheel. It requires a steady throttle hand, but didn’t prove to be too much for our novice testers to manage.

Changes to the 449cc four-stroke motor include revised cam timing and ECU settings for improved mid- to high-range performance. The cylinder sleeve and right side crankcase get reinforced for improved durability. The piston is also new (along with the pin), becoming stronger and lighter overall. A new crankshaft and new camshaft complement the engine changes, also aiming at improving torque and traction. The clutch, clutch plates, head pipe and radiators are also new.

The chassis also showcases a host of modifications from the ’09, although aesthetically it doesn’t appear much different at all. The fork and shock are new, both featuring stiffer spring rates (a 4.6 to a 4.7 up front and a 5.3 to a 5.5 on the shock). The swingarm is all-new, and the ’10 also receives a revised linkage ratio aimed at improving static ride height.

Engineers aimed at giving the KX450F better overall balance and stability – especially for more aggressive riders. What we discovered from our first impression is that the 2010 KX likes to be ridden hard. The harder you push it, the better it seems to perform.

Pala Raceway provided us with deep-disked terrain that really let the 450 throw some dirt around. On such a beautiful summer afternoon, we decided to double-dip and swing by Perris for a night-moto session on our way home. The KX really shined at the smoother and jumpier Perris circuit and contrary to what we anticipated, power was still very useable on the harder-packed terrain.

Suspension action on both the fork and shock remains quite plush on the initial stroke, letting it gobble up chop and square edges. It also retaining excellent bottoming resistance making it quite forgiving when coming up short or over-clearing jumps  With its aptitude for jumping, quick-turning, and accelerating hard, our expert tester named it a good Supercross bike.

After our first day with the 2010 KX450F, we’ve discovered that it’s an all-around more potent weapon, but we’re also glad it hasn’t lost any of its manners in the process.

Watch the pages of Cycle News for our full review of the 2010 Kawasaki KX450F.