Kawasaki introduces redesigned KX450F, KX250F for 2009

Kawasaki’s race-winning 450 and 250 four-stroke motocrossers will get a thorough overhaul for 2009, the company announced.

In addition, Kawasaki’s entire motocross lineup and the majority of its off-road line will be offered in optional Monster Energy livery, featuring black bodywork and wheels, green hubs, a silver frame and a Monster Energy graphics set.

KX450F

The KX450F gets a host of upgrades, including batteryless fuel-injection, an all-new chassis and updated bodywork—marking the most radical changes to the machine since its 2006 debut.

According to Kawasaki, the new EFI system eliminates the need to adjust engine settings to suit track and climate conditions and offers stable fuel-metering even in tough motocross conditions. The company claims the big single can be started within three rotations of the crankshaft, using only the electricity generated through the kickstarter.

The new engine is more compact and lighter, with a 5mm shorter cylinder head that also features revised intake and exhaust ports for improved engine performance through the entire rpm range. A new piston with a reshaped top surface raises the engine’s compression ratio from 12.0 to 12.5:1 and works in conjunction with a new one-piece titanium exhaust pipe to provide improved low-mid range performance.

A blend of forged, extruded and cast parts, the revised frame is 1.8 pounds lighter than its predecessor and offers an increase in stability and traction, thanks to improved rigidity balance. An updated swingarm, revised forks and a beefier rear shock round out the suspension updates for 2009.

Ergonomic updates to the 450F include slimmer bodywork, a narrower seat and wider footpegs.

The 2009 KX405F carries an MSRP of $7,549 in Lime Green and $7,749 in Monster Energy ebony (above, right).

KX250F

The 250cc single also receives a host of updates for 2009, including changes to the engine, chassis and ergonomics.

The liquid-cooled motor features a cylinder head with a new intake port design that’s smoother, freer flowing, better sealed and holds new stronger titanium valves with a longer service life. A revised crank web significantly increases crankshaft balance, resulting in reduced engine vibration, smoother power delivery and a noticeable improvement in low rpm throttle response, claims Kawasaki. Engine oil volume is lowered to 1.3 liters to reduce weight and mechanical loss, while a new KX450F type crankcase scavenge pump oil filter was added for easier maintenance.

A new aluminum perimeter frame and sub-frame uses fewer parts and gussets and is 2.2 pounds lighter than the 2008 model, while providing enhanced stability and improved drive from the rear tire. The KX250F also features an updated “D” section swingarm, a beefier rear shock and titanium-coated inner tubes on the front forks.

Like its big brother, the 250F also gets slimmer bodywork, a narrower seat and wider footpegs.

The 2009 KX250F carries an MSRP of $6,499 in Lime Green and $6,699 in Monster Energy ebony.

For more information on these and other new models in the 2009 Kawasaki lineup, see www.kawasaki.com.