Introduction
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 KX™450F 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°
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
'09 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 "D"
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 '09 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™, 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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Features
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 60µ for smooth power deliver and
improved engine at partial throttle
- 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°, the optimum angle for improved mid-range
power, which corresponds to the intake ports of the new head
design and is an improved position compared to competing products
New ECU
- No battery needed, saving weight; the engine can be started
with only three rotations of the crankshaft using the electricity
generated by a single kick of the starter
- The system delivers electricity to FI system in sequence for
quick starting: first the ECU, then the fuel pump, and finally
the injector
- 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
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° 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 cylinder head 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
- 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
- End result is reduced engine vibration, smoother power delivery
and increased performance, with a noticeably snappier response
at low rpm
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 response 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
improves 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 for a slimmer
overall width main spars shape - narrowing near the bend below
the seat for a riding position, then widening at the ankles to
offer better grip
- Slimmer head pipe, new cross section and a down tube that is
formed with a swaging (squeezing and hammering) process and has
a smaller cast bracket add up to more weight savings
- 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
- Revised chassis dimensions contribute to improved handling
- Swingarm pivot is located 3mm higher in the frame for improved
rear wheel traction
- New sub-frame is lighter via larger diameter tubing with thinner
walls, yet still provides a secure mounting for the new silencer
New Aluminum Swingarm
- New tapered "D" shape, vice rectangle design that
is 5mm taller at the front (74 to 79mm) and 2mm shorter at the
rear (60 to 58mm)
- New cross bracket design for enhanced rigidity
- Alloy swingarm uses a cast front section, tapered hydroformed
spars and forged chain adjusters
- New swingarm design is approximately 0.4 lbs lighter and improves
stability, rigidity and rear wheel traction
- Uni-Trak® rear suspension system with the suspension arm
mounted below the swingarm, allowing a longer rear suspension
stroke and more precise tuning
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 '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
- 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 just like the factory racers
- Foot peg width (front to rear) increased from 46mm on previous
model to 50mm for improved feel
- New seat design that's slimmer with firmer urethane for improved
ergonomics and feel
- Seat has a slip-resistant top surface for good grip when seated
and smooth sides for excellent rider mobility
New Chain Guide
- Slimmer 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, for easy
clutch cable play adjustment 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
Optional ECU Setting Tool Available
- 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.
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Technical Specifications
Engine: Liquid-cooled, four-stroke
single with DOHC and four valve cylinder head
Displacement: 449cc
Bore x stroke: 96.0 x 62.1mm
Compression ratio: 12.5:1
Fuel Injection: 43mm Keihin Throttle body
Ignition: Digital DC-CDI
Transmission: Five-speed
Rake / trail: 26.7 degrees / 4.6 in.
Front suspension / wheel travel: 48mm inverted, Kayaba AOS with
DLC coated sliders, 22-position compression and 20-position rebound
dampening adjustment / 12.4 in.
Rear suspension / wheel travel: UNI-TRAK® linkage system
and Kayaba shock with 22-position low-speed and stepless high-speed
compression dampening, 22-position rebound dampening and fully
adjustable spring preload / 12.4 in.
Front tire: 90/100-21
Rear tire: 120/80-19
Front brake: Single semi-floating 250mm petal disc with dual
piston caliper
Rear brake: Single 240mm petal disc with single-piston caliper
Overall length: 86.0 in.
Overall width: 32.3 in.
Overall height: 50.4 in.
Wheelbase: 58.3 in.
Ground clearance: 13.4 in.
Seat height: 38.0 in.
Curb weight: 247.2 lbs.
Fuel capacity: 1.8 gal.
Color: Lime Green
* Price and specifications subject to change
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