2009 KAWASAKI KX450F

On Sep 14, 2008 Last updated Feb 23, 2018

A leaner, stronger and EFI equipped racing thoroughbred

Comprehensively re-designed with a new fuel-injected engine, chassis, bodywork and extensive durability enhancements, the 2009 Kawasaki KX450F motocrosser is sleeker, faster and more high-tech than ever. Although it has undergone the biggest makeover since its original 2006 debut, the new KX450F 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 Degree 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 EFI system’s increased electrical needs are handled by a new larger AC generator rotor that also increases the engine’s 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 to help achieve a crankshaft balance factor of close to 60 percent. This is on par with Kawasaki’s factory racers. The end result of these changes is reduced engine vibration, smoother power delivery and a noticeable improvement in low rpm throttle response.
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. Rounding out the powertrain enhancements is a larger-volume silencer body that’s able to meet future noise regulations. It uses long-fiber packing that lasts longer and extends service intervals.

Overall, the new KX450F’s ample power is 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 aluminum frame, suspension components and settings was focused on translating this broad powerband and responsive throttle into better drive off the corners. Other goals of the 2009 revisions were lighter handling and a slimmer chassis with an optimized rigidity balance. To achieve these aims, every part was examined or revised. The cross-sections of the main spars were shrunk, the head pipe is slimmer and a new process was used to form the down tube, while the reshaped sub-frame is narrower yet stronger.

A blend of forged, extruded and cast parts, the revised chassis dimensions, parts reduction and gussets of the new frame equal a 1.8 pounds weight savings and an increase in stability and traction, thanks to improved rigidity balance.

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

Complementing the chassis balance with settings optimized for experienced racers, the KX450F’s suspension offers a host of new features for better cornering and sharper 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 which offers a 15 percent reduction in stiction when the fork is exposed to lateral forces that 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 24 to 23mm further enhanced the new KX450F’s lighter handling and increased its 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 50 mm piston (previously 46 mm). 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 enhancements are not limited to internal components on the new KX450F. The larger, resin skid plate and narrower, longer lasting chain guide both offer better protection without increased weight and are examples of the race-oriented durability improvements that abound on the new KX450F.

In addition to giving the 2009 KX450F a stunning new look, the bodywork was completely revised with the main focus on rider comfort and ergonomics. Offering the rider an even slimmer interface with a natural positioning makes it easier for racers to relax and go fast. Included in the sleek new bodywork styling are one-piece dual injected, two-tone green and white plastic shrouds and side number plates. This new bodywork translates into less time hassling with backgrounds and graphics and more time collecting trophies.

A slimmer new seat design with firmer urethane, 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 ankles to provide the rider with better feel and control. Completing the rider interface improvements are wider 50mm footpegs that offer increased grip and a more comfortable platform.

The 2009 KX450F will be available in Kawasaki Lime Green, with black alumite-coated rims and aggressive graphics for a factory appearance.

Racers who ride their KX450F at designated events are eligible to receive support from Team Green’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.

Kawasaki Motors Corp., U.S.A. (KMC) markets and distributes Kawasaki motorcycles, ATVs, personal watercraft, utility vehicles and recreation utility vehicles through a network of more than 1,500 independent retailers, with an additional 8,000 retailers specializing in Kawasaki power products and general purpose engines. KMC and its affiliates employ nearly 3,650 people in the United States, with 430 of them located at KMC’s Irvine, California headquarters.

Kawasaki’s tagline, “Let the good times roll,”VbCrLf is recognized worldwide. The Kawasaki brand has become synonymous with powerful, stylish motorcycles for over four decades. Information about Kawasaki’s complete line of recreational products and Kawasaki affiliates can be found on the Internet at www.kawasaki.com.

2009 Kawasaki KX450F

Features and Benefits
All-New Fuel Injection
Improved Engine Performance and Greater Engine Durability
All-New Chassis and Styling
Improved DLC Coated Fork

All-New Fuel Injection
Self adjusts to atmospheric changes for easier starting, sharper throttle response and optimized power, and power stability when jumping/landing
Ultra-fine atomizing injector with 12 holes sprays particles with a droplet size of 60¬ (same as 2007 Ninja ZX-10R) for smooth power deliver and improved engine at partial throttle
Improved Performance in Transition Zone
43mm throttle body uses a progressive throttle linkage to deliver airflow in much the same way as an FCR carburetor. Using two linked shafts, the throttle body opens more quickly after reaching the 3/8 open position
Lightweight throttle body is approximately half the weight of a FCR carburetor, saving over one pound in weight
Fast-idle knob on the throttle body allows riders to increase engine speed when starting a cold engine

Optimized Injector Angle
Injector set at 45 degree, the optimum angle for improved mid-range power, also corresponds to the intake ports of the new head design
Improved positioning compared to competing products

New ECU
No Battery needed; the engine can be started with only three rotations of the crankshaft using the electricity generated by a single kick of the starter
Less weight without a battery
The system delivers electricity to FI system in sequence for quick starting: first the ECU, then the fuel pump, and finally the injector
Starting can be accomplished in a single kick
The compact, lightweight ECU, located on the front of the steering head behind the number plate, was designed specifically for motocross use. The fuel pump relay is built in to the ECU to help cope with the shocks and vibrations of motocross riding

New Lightweight Aluminum Fuel Pump
Located in the fuel tank
Features a rubber fuel filter cover that wraps around the inlet port and acts as a fuel trap to help ensure a stable fuel supply during vigorous motocross riding
Fuel return hose from the pressure regulator helps ensure there is always fuel in the inlet port, preventing stalls due to fuel splashing and enabling riders to use all the fuel
New 1.8 gallon fuel tank is lighter and formed using a rotational molding process

Optional User ECU Setting Tool
Allows racers to reprogram the ECU’s data maps for volume of fuel injected and ignition timing to alter engine characteristics to suit rider preference
The tool can also be used as a data logger, recording up to six hours of data for engine rpm, angle of throttle opening, etc.

Improved Engine Performance
449cc liquid-cooled, DOHC, four-stroke single
New piston with reshaped head increases compression ratio from 12.0 to 12.5:1 for improved low and mid range performance
Low-friction coating on the piston skirt reduces mechanical loss
Revised piston jet injects oil at a new angle for improved piston cooling
Piston jet nozzle opening was improved to minimize oil gathering for a better contribution to piston cooling
A forward lean angle of 3 degrees puts the engine in the ideal position for maximum traction
Tuned for a broad powerband with the torque curve set just under the wheel spin threshold
High-acceleration cams help the engine rev quickly
Equipped with an automatic compression release (ACR) system for quick and easy starting. The dual-weight centrifugal decompression system is fitted to the exhaust cam
Maintenance free screw-type automatic cam chain adjuster
Larger flap inside the airbox helps prevent the ingress of mud and water

New Top End
Revised intake and exhaust ports for improved engine performance at all rpm
Reduced height from 105 to 100mm for a more compact, lighter engine
Titanium 36mm intake and 31mm exhaust valves with aluminum spring retainers reduce reciprocating weight and cylinder height and help ensure reliable valve control at high rpm
New high-strength material with finer metal grain for intake valves offers about a 50 percent greater resistance to fatigue
Double valve springs allow a short cylinder head height and help ensure stable valve operation
Dual overhead, lightweight camshafts lobes and tappet surfaces feature a soft-nitride surface treatment for long wear and high-rpm reliability
Asymmetrical high-acceleration cams and the special coating on the intake ports yield high intake efficiency at all rpm

New Crankshaft Design
Improved traction with increased rotational inertia via a larger diameter AC Generator rotor
Crankshaft was reshaped with its rotational inertia unchanged to enable the balance factor to remain the same with bigger ACG rotor and provide weight savings
Wedge-shaped crank web increases offsetting moment for high crankshaft balance factor of 60 percent, on par with Kawasaki’s factory racers
End result is reduced engine vibration, smoother power delivery and increased performance, with a noticeably snappier response at low rpm
New crankshaft large bearing with an increased load capacity, 2mm longer bearing rollers and a 40 percent improvement in durability
Crankshaft and connecting rod received a carburizing and quenching treatment for additional rigidity

Easier Starting
Greater electrical output from the bigger ACG rotor provides the necessary electrical power that allows a battery-less FI system with kick starting and provides smoother engine performance
New ACR with increased lift from 0.5 to 1.0mm, reduces kicking power necessary to start
Better Cooling
Very slim, high-capacity Denso radiators feature tightly packed cores and a fin design that delivers superior cooling efficiency
Radiator louvers increased from three to four and decreased in size and angle for less overlap and higher air flow
Brace bar reinforces the radiator bracket and adds to the KX450F’s durability

Smooth-Shifting, Close-Ratio 5-Speed Transmission
5-Speed transmission and low-rpm engine combination offers riders more gear options for traversing rough sections or getting into the rhythm of a course easily so they can focus more on racing
Sprocket-style chain drive roller reduces the effect of driveline lash, helping smooth engine braking and facilitating additional corner entry control

New Titanium Exhaust Pipe
One-piece titanium exhaust pipe with revised length and diameter is not tapered, and both enables the improved low-mid range performance as well as contributing to improved ergonomics
New silencer body has increased volume to meet future noise regulations – currently 99dB

Lighter, slimmer chassis
New main spars with a smaller cross-section down from 70mm tall and 27mm wide to 68mm and 24mm, respectively
More weight savings via a slimmer head pipe, a new cross section and a down tube that is now formed with a swaging (squeezing and hammering) process and has a smaller cast bracket
Revised chassis dimensions contribute to improved handling
Swingarm pivot is located 3mm higher in the frame for improved rear wheel traction
New sub-frame with a larger diameter down tube that’s 6mm narrower at the main spars
Parts revisions combine for about a 1.8 pound lighter new aluminum perimeter frame that offers increased riding stability and traction through a better rigidity balance

New Aluminum Swingarm
New taperedVbCrLf shape, vice rectangle design that is 5mm taller at the front (74 to 79mm) and 2mm shorter at the rear (60 to 58mm)
New swingarm has revised rigidity, which contributes to improved riding stability, and is approximately 0.4 lbs lighter
New cross bracket design for enhanced rigidity
Alloy swingarm uses a cast front section, tapered hydroformed spars and forged chain adjusters
Uni-Trak rear suspension system with the suspension arm mounted below the swingarm, allowing a longer rear suspension stroke and more precise tuning
Design improves stability, rigidity and rear wheel traction

New Front Fork
Kayaba Air-Oil-Separate (AOS) fork keeps oil and air in separate chambers for stable damping performance during long motos. Low-friction fork seals contribute to smooth action
New Diamond-Like Carbon (DLC) coating on the outer surface of the inner fork tubes offers a 15 percent reduction in stiction from 2008 KX450F when the fork is exposed to lateral forces that would usually hamper slide action. The result is improved fork response, especially during cornering
Friction-reducing Kashima Coat on the inside of the fork outer tubes contributes to smoother suspension action (especially at the initial part of the stroke) and a better ride feel
Revising the frame’s rigidity balance, amending the suspension settings, and reducing the fork offset from 24mm to 23mm gives the KX450F lighter handling and increased front wheel traction
Optimized rigidity balance via increased rigidity in the reshaped upper triple clamp and decreased rigidity in the new outer fork tubes
Enlarged, wrap around black fork tube guards provide greater protection for the inner tubes
Revised race-oriented suspension settings offer improved over-all performance

New Rear Shock
Kayaba rear shock has a new cylinder body design and a larger 50mm piston (previously 46mm)
Improved response, damping and bottoming performance result in better ride feel and terrain following capability
Rear shock features dual compression adjustability, allowing high-speed and low-speed damping to be tuned separately
Also features Kashima Coat treatment on the cylinder for reduced friction and smoother suspension action
Easier accessibility for tuning
Revised rear suspension settings and ideal linkage ratios derived from extensive rider testing produce an over-all improved and race-oriented performance

Improved Rider Interface and Styling
All-new body work and graphics
New dual injected 2-tone, one-piece plastic shrouds and side number plates
Right side panel has an added passageway to aid in cooling the silencer
Black plastic covers, triple clamps, engine covers, and black alumite coated rims
Foot peg width (front to rear) increased from 46mm on previous model to 50mm for improved feel
Frame is wider at the ankles to offer better grip, narrows near the bend below the seat to allow a slim riding position
New seat design
Seat has a slip-resistant top surface for good grip when seated and smooth sides for excellent rider mobility

New Chain Guide
More slim and compact, down from 42.7 to 34mm wide, with 2mm thicker wear pad
Reduced weight and longer wear

Additional Features
New skid plate made of resin material offers greater protection without a weight increase
Larger front brake lever boot offers increased protection against dust
Clutch cable boot features a large quick adjuster, making it easy for riders to adjust play in the clutch cable while on the fly
Throttle grip has a one-piece collar that provides additional stability during throttle operation
Lightweight short-length grips feature a pattern designed to provide excellent grip
Rear caliper guard protects the caliper from damage
Ribless rear hub and butted spokes reduced unsprung weight