2007 Kawasaki KLX450
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Imagine a purpose-built off-road race machine armed with class-leading 4-
stroke engine technology and race-proven chassis know-how from the fastpaced
world of motocrossing. That is exactly what the competition has feared,
and what Kawasaki fans have been waiting for, since the debut of the highly
acclaimed KX450F two short years ago - and just what Kawasaki is offering in
the all-new 2008 KLX450R, the company's lightest, fastest and most powerful
big-bore 4-stroke off-road race machine ever.
The KLX450R gets its key components straight out of our mighty KX450F motocrosser
and adapts them for off-road racing. The KX450F's high-powered, lightweight 4-stroke
engine has been tweaked for more low-end torque and is mated to a special wide-ratio
5-speed transmission - and of course comes with an electric starter. The lightweight
all-aluminium chassis has been thoroughly scrutinised for its ability to perform under the
toughest of off-road racing conditions and to make it easier to control in a variety of
terrain. The high-spec AOS inverted fork and superb rear suspension from the KX450F
have been tuned for rougher conditions and to minimise rider fatigue over long
With the ground-breaking, all-new high-performance KLX450R, the competition
have every reason to be afraid. Out of the crate, off-road competitors can now
enjoy the same incredible engine and the same outstanding frame and
suspension technologies as our class-leading KX450F, but in a bike purposebuilt
to excel in off-road racing.
Adapting Championship-Winning KX 4-Stroke
The KLX450R's powerplant comes directly from our mighty KX450F motocrosser. To
transform the liquid-cooled 449 cm3 KX450F power unit into an off-road racing winner,
the highly acclaimed engine was tuned for maximum low- and mid-range performance.
The result is a wide spread of responsive, high-traction torque and superior throttle
control for low-speed manoeuvring. The numerous modifications consider the variety of
conditions riders face in open-course racing and also contribute enhanced durability
and reliability to ensure that both man and machine reach the finish line.
Engine tuned for low-mid range torque and superb throttle control
Improved low and mid-range power characteristics for gutsy response when
climbing hills, riding in the mud or in other poor-traction, low-speed conditions.
Revised cam lift and timing boost low- and mid-range torque.
Exhaust valve diameter is decreased by 1 mm for improved exhaust efficiency.
Flywheel mass is double that of the KX450F to provide ultra-smooth engine
The KLX450R's linear power curve features plenty of over-rev, giving riders
ample latitude in choosing their shift intervals.
The wide-ratio 5-speed transmission features ratios selected specially for offroad
The functional design of the clutch lever assembly results in a straighter run for the
clutch cable, offering smooth, low-effort operation. The clutch's excellent feel is
especially welcome in the often tight and low-speed off-road racing environment.
Electric starter and enhanced durability
An electric starter was added. Having both electric and kick starters mean the
bike can be quickly restarted if the engine stalls during an event. The highcapacity
starter motor is compact, yet high-output ensures quick and reliable
starts under all conditions. The battery is located beneath the seat and behind
While the lightweight intake valves from the KX remain unchanged, steel exhaust
valves replace the KX's titanium units for improved durability.
The transmission's gears are designed for high durability.
For efficient cooling during long enduros the radiator is fitted with a reservoir tank.
Sealed chain is ideal for long-distance events.
Performance features inherited from the KX450F
The engine was tuned so that the torque curve follows the limit of running
resistance for as long as possible. (Unchecked, engine torque can exceed this
limit, resulting in wheel spin, which does nothing to help forward momentum.)
Efforts were made to achieve the widest possible torque band, so that traction
efficiency would be maximised for a greater part of the rev range.
Asymmetrical high-acceleration cams yield high intake efficiency.
Piston skirt features a low-friction coating for reduced mechanical loss.
Aluminium valve spring retainers contribute to reduced reciprocating weight.
Double valve springs also help ensure stable valve operation and allow a short
cylinder head height.
The airbox arrestor features a two-screen design. Space between the screens
reduces resistance for improved intake efficiency.
The screw-type adjuster on the cam chain tensioner is equipped with a pressure
spring. Because the system automatically eliminates the vibration caused by a
loose cam chain, it greatly reduces the chance of a mishap during a race. (Nonautomatic
systems that are tuned incorrectly can actually adversely affect valve
timing by putting too much pressure on the cam chain.)
In the event of a stalled engine during a race, getting it started again as soon as
possible is a racer's first priority, so the KLX450R is equipped with the best
automatic compression release (ACR) system available. The dual-weight
centrifugal decompression system fitted to the exhaust cam eases starting in
much the same way as a conventional lever-type system.
Tuned For Maximum Off-Road Performance
In order to ensure superb control and the best possible road-holding performance over a
variety of terrain, suspension quality could not be compromised. The KLX450R shares
the same top-of-the-line suspension as the championship-winning KX450F.
The Kayaba AOS (Air-Oil-Separate) inverted fork from the KX450F offers superb
damping and steering precision. Where the KX settings maximise sprint and
jumping performance, for the KLX, settings were chosen for light, easy handling
characteristics. Oil and air are kept in separate chambers for stable damping
performance during long motos. Low-friction fork seals contribute to smooth
The New Uni-Trak rear suspension system mounts the suspension arm below the
swingarm, allowing a longer rear suspension stroke. The longer stroke in turn
allows more precise rear suspension tuning.
The rear shock features dual compression adjustability, allowing high-speed and
low-speed damping to be tuned separately.
Responsive, light-handling chassis for minimum fatigue
Starting with the KX450F's lightweight aluminium frame and superb suspension
package as a base, the KLX450R's chassis is set up to offer nimble handling qualities
in the rough stuff and minimise rider fatigue during long motos. Whether negotiating
narrow trails or manoeuvring between rocks and trees, the KLX450R has the lightweight and responsive handling qualities needed to enable riders to go the distance in off-road racing.
The lightweight all-aluminium perimeter frame - straight from the KX450F - is a
composite structure comprising forged, extruded and cast components.
The frame's rigidity balance contributes to a package that is both quick-turning
and light handling.
A works-style Renthal (standard-type) aluminium handlebar is standard
Like the KX450F, the KLX450R features petal brake discs front and rear. In
addition to helping reduce unsprung weight, the wave shapes of the petal discs
help clean the brake pads for more efficient braking performance.
An 18" rear wheel (KX450F: 19") offers a wide selection of tyres to choose from.
The seat is wider than the KX450F's for comfort during long motos. The seat
uses a slip-resistant top surface for good grip when seated and smooth sides for
excellent rider mobility.
A two-piece radiator shroud design allows a hole where the shroud covers the
upper frame spars, ensuring a narrow riding position at the knees. Compared to
the KX shrouds, the KLX shroud design is optimised for a seated position.
Like the KX450F, the frame widens at the ankles to offer the rider better grip and
is narrower near the bend below the seat to allow a slim riding position.
The seat, tank and shrouds were designed to integrate perfectly, creating a single
smooth surface for maximum rider mobility.
Fully Equipped For Off-Road Racing
The KLX450R comes straight from the factory with everything needed to win in opencourse
racing. Each component has been specially developed to enhance the
KLX450R's off-road racing performance while adding as little weight as possible. In
fact, the KLX450R weighs only about 10 kg more than the KX450F.
Off-road racing equipment
Lightweight digital instrumentation includes a speedometer, twin tripmeter,
odometer and clock.
Lightweight plastic fuel tank has an 8 litre capacity (KX450F: 7.2 litres) and the
tank petcock is fitted with a reserve. Construction of the plastic tank meets strict
U.S. environmental regulations.
Compact lighting package includes a 35 W headlight with lightweight plastic lens.
An ultra-compact and energy efficient LED tail lamp is used.
The side covers share their design with the KX450F, although the holes have
been eliminated to prevent the ingress of water. The left-side cover features a
two-piece construction with a special "door" that allows easy access to the air
Engine guards protect both sides of the engine. (KX450F has a right-side guard
Like the KX450F, a works-style aluminium skid plate also comes as standard
A side stand is fitted as standard equipment.
Californian models feature a secondary air system to enable them to meet strict
Engine Type - Liquid-cooled, 4-stroke Single
Displacement - 449 cm3
Bore and Stroke - 96.0 x 62.1 mm
Compression ratio - 12.0:1
Valve system - DOHC, 4 valves
Fuel system - Carburettor: Keihin FCR
Ignition - Digital AC-CDI
Starting - Electric, primary kick
Lubrication - Forced lubrication, semi-dry sump
Transmission - 5-speed, return
Final drive - Sealed chain
Primary reduction ratio - 2.727 (60/22)
Clutch - Wet multi-disc, manual
Frame Type - Perimeter, aluminium
Tyre - front; 80/100-21 51M, rear; 110/100-18 64M
Caster (rake) - 27.1o
Trail - 117 mm
Steering angle (left/right) - 42o / 42o
Suspension - Front: Compression damping, Rebound damping, Spring preload, 48 mm upside-down AOS-type telescopic fork
22-way, 20-way, Rear: Compression damping, Rebound damping, New Uni-Trak, 22-way (low-speed), 2-turns or more (high-speed)
22-way, Fully adjustable
Brakes - Front: Caliper, Single semi-floating 250 mm petal disc, Dual-piston, Rear: Caliper, Single 240 mm petal disc, Single-piston
Fuel capacity - 8 litres
The specifications mentioned here apply to and have been achieved by production models under
standard operating conditions. We intend only to give a fair description of the vehicle and its performance
capabilities but these specifications may not apply to every machine supplied for sale. Kawasaki Heavy
Industries, Ltd. reserves the right to alter specifications without prior notice. Equipment illustrated and
specifications may vary to meet individual markets. Available colours may vary by market.