2009 Top Kawasaki KX 450F Motorcycle

Sporting a new chassis, fuel-injected engine, bodywork and durability refinements, the 2009 Top Kawasaki KX™450F motocrosser represents high-tech racetrack domination. However, the all black KX450F Monster Energy® promises a cranked-up heart rate for anyone with a pulse, thanks to its black bodywork and wheels, green hubs and silver frame; highlighted by the aggressive Monster Energy graphics package.

For racers looking to demoralize the competition, the sinister looking KX450F Monster Energy is the weapon of choice. Underneath its tough new appearance, the KX450F has undergone the biggest makeover since its original 2006 debut, but it still shares a clear bloodline with its championship-winning predecessors.

The upgrade to Electronic Fuel Injection (EFI) eliminates the need to adjust engine settings to suit track and climate conditions and offers stable fuel-metering even in tough motocross conditions –without sacrificing the hard-hitting character of its predecessor. The new EFI system includes a compact lightweight ECU, a 43mm throttle body, a newly designed lightweight aluminum in-tank fuel pump and an ultra-fine atomizing injector. Set at a 45° angle for ideal mid-range power, the 12-hole injector sprays precise 60 micron fuel particles for smooth power delivery and improved engine response at partial throttle.

Designed specifically for motocross, the KX450F’s lightweight EFI system doesn’t require a battery –the engine can be started within three rotations of the crankshaft, using only the electricity generated through the kickstarter. Kawasaki engineers achieved single-kick start capability by having the ECU power-up at the initial movement of the kickstarter. The system delivers electricity in the following order: ECU, fuel pump, and then injector.

The greater electrical needs are handled by a larger AC generator rotor that also increased the rotational inertia. A reshaped and lighter crankshaft, with its rotational inertia unchanged, balances out the bigger ACG rotor. A wedge-shaped crank web increases the offsetting moment for a high crankshaft balance factor of close to 60 percent, on par with Kawasaki’s factory racers. The end result of these changes is reduced engine vibration, smoother power delivery and a noticeably snappier response at low rpm.

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 at all rpm. A new piston with a reshaped top surface raises the compression ratio from 12.0 to 12.5 and along with the new one-piece titanium exhaust pipe contributes to improved low-mid range performance. Finishing out the engine revisions is a new silencer body with larger volume able to meet future noise regulations. It uses long-fiber packing that lasts longer and extends time between repacking.

Overall, the KX450F’s ample power is now delivered in a smoother, more user-friendly manner with a linear low-rpm throttle response and torque delivery that reduces fatigue and allows riders to go faster for more laps.

Design of the highly rigid aluminum frame, suspension components and settings were focused on translating this broad powerband and responsive throttle into better drive. Other goals of the ’09 revisions were lighter handling and a slimmer chassis with an optimized rigidity balance. To achieve these aims, no piece was left examined or untouched. The cross-sections of the main spars were shrunk, the head pipe is slimmer and a new process is used to form the down tube that leaves it with a smaller cast bracket while the sub-frame was reshaped narrower but with a beefier down tube.

A blend of forged, extruded and cast parts, the revised chassis dimensions and fewer frame parts and gussets of the new frame total up to approximately 1.8 fewer pounds and an increase in riding stability and traction through a better rigidity balance.

Working in conjunction with the frame revisions is a new aluminum swingarm now pivoting from a 3mm higher position on the frame. It is now a lighter, more tapered design with a “D” profile and a new cross bracket. A longer rear suspension stroke, and thus more precise rear suspension tuning, was achieved by mounting the suspension arm of the Uni-Trak® rear suspension system is now below the swingarm.

Complementing the chassis balance with settings set to suit race-experienced riders, the KX450F suspension has a host of new features for better cornering and handling. The Kayaba Air-Oil-Separate (AOS) fork has a new Diamond-Like Carbon (DLC) coating on the outer surface of the inner fork tubes offers a 15 percent reduction in stiction from ‘08 KX450F when the fork is exposed to lateral forces that would usually hamper slide action. The result is improved fork response, especially during cornering. The overall suspension action is even smoother due to the friction-reducing Kashima Coat treatment on the inside surfaces of the outer fork tubes and the rear shock reservoir.

Increasing the rigidity in the reshaped upper triple clamp and decreasing it in the new outer fork tubes optimized the rigidity balance of the front end. Adjusting the race-oriented suspension settings, and reducing the fork offset from 24mm to 23mm further enhanced the new KX450F’s lighter handling and increased front wheel traction. Enlarged, wrap around black fork tube guards provide greater protection for the inner tubes.

Matching the smooth action of the fork, the Kayaba rear shock received a new body design and a larger 50mm piston (previously 46mm). Its improved response, damping and bottoming performance equate to a better ride and increased maneuvering precision. It also features a Kashima Coat treatment on the shock internals. Its easily accessible dual compression adjustability - allowing high-speed and low-speed damping to be tuned separately - gives mechanics and riders the ability to fine-tune for difficult track conditions.

Durability isn’t limited to internal components on the new Kawasaki model. The larger, resin skid plate and the narrower and longer lasting chain guide both offer greater protection without higher weight and are examples of the race-oriented durability increases that abound on the new KX450F.

In addition to giving the all black ’09 KX450F Monster Energy a stunning look, the bodywork was completely revised with the main focus on rider comfort and ergonomics with natural positioning. With sleek new bodywork styling featuring one-piece plastic shrouds and side number plate, the new KX450F offers a slimmer rider interface that makes it even easier to go fast, win races and collect more trophies.

A slimmer new seat design with firmer urethane foam, a non-slip top surface and smooth sides provides good seated grip and excellent rider mobility. The frame echoes the slim profile at the top, but widens at the lower end by the by the ankles to provide better grip for the rider. Completing the rider interface improvements are wider, front-to-rear, 50mm footpegs that offer increased grip and improved feel.

Racers who ride their KX450F at designated events are eligible to receive support from Team Green™, Kawasaki’s amateur racing support program. Each year, Team Green provides regional support vehicles and highly trained technicians at more than 100 events, offering technical information and assistance to those who race Kawasaki products. Kawasaki also offers a comprehensive contingency program for amateur and professional riders who place well at designated events.

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