2012 Kawasaki KX450
RACE-PROVEN PERFORMANCE AND
FACTORY KNOW-HOW THAT GIVES MID-EXPERT RIDERS AN EDGE
The KX450F base package provides an
excellent platform for experienced racers to win races
in the top classes. Design of the highly rigid aluminium
frame, suspension components and settings focused
on ensuring control is maintained during high-speed
riding – especially in straight lines –
to enable race-experienced riders to ride full out.
And to deliver holeshot-winning performance –
a key factor that can mean the difference
between running up front and winning, or getting stuck
mid-pack – chassis geometry and the hard-hitting
4-stroke engine’s wide powerband were designed
to maximise rear wheel traction. The combination is
a proven race-winner, with Kawasaki racers regular
Complementing the race-winning performance
of its predecessor’s highly acclaimed engine
and nimble high-speed chassis, the 2012 KX450F adds
numerous new factory-inspired features designed to
give serious riders an edge on the track. The MX industry’s
first production-use of a Launch Control Mode, a new
with 3 easily selectable maps, and an adjustable riding
position that riders can tailor to suit their size
and riding style make the new KX450F an even more
potent weapon on the track.
FACTORY KNOW-HOW THAT GIVES
YOU AN EDGE
KX motocrossers have long drawn on
works technology to offer riders the best possible
performance right out of the box. The 2012 KX450F
is equipped with a host of new factory features to
give riders an edge when lining up at the start gate.
The holeshot advantage: Launch Control
Mode The 2012 KX450F features a launch control system
similar to that on our factory racers. With the simple
press of a button, riders can activate a separate
designed to ensure efficient race starts in slippery
conditions. (The Launch Control Mode map retards ignition
timing, allowing tyres to gain grip in low-traction
situations, and allowing riders to focus on their
Launch Control Mode has the greatest effect within
the first few seconds of releasing the clutch off
the start. This is the most crucial time for riders
to get ahead of their rivals so they are better positioned
going into the first corner.
Even for top-level riders, controlling the massive
power of a 450cc-class motocrosser off the start requires
a high degree of throttle control and clutch finesse.
By slightly reducing this power, Launch Control Mode
helps riders maximise traction, increasing the chance
of getting a good start.
Launch Control Mode works in 1st and 2nd gear (and
Neutral). Once the rider shifts into 3rd gear, the
system is automatically disengaged, switching back
to the normal engine map.
System designed to the same specifications as that
of our AMA factory racers. Easy engine tuning: DFI
Setting Data Selection (3 map choices) Instead of
a single engine map, the new ECU features three (four,
counting the Launch Control Mode map).
Initial settings for the three maps are: Standard,
Hard (conditions) and Soft (conditions). Using provided
DFI couplers, riders are able to easily switch between
the three maps to suit riding conditions. Plugging
in each of the 4-pin couplers activates the corresponding
(Plug is conveniently located on the
right side of the head pipe for easy access without
having to remove any parts.)
Each of the three maps can be reprogrammed using the
optional KX FI Calibration Kit. (Please see below.)
Precision engine tuning: KX FI Calibration
The KX FI Calibration Kit is the same
kit used by Kawasaki’s works teams in Europe
and the U.S. The kit enables expert riders to adjust
engine characteristics (by rewriting actual data maps)
to suit their preference, record riding data, and
analyse their riding data to further fine-tune their
The KX FI Calibration Kit contains
KX Racing software, an ECU controller, mounting brackets
and damper and USB cable. In addition to the kit,
a PC and 12 V battery are all that is required.
While the kit is designed to satisfy racers and expert
riders, it is simple and hassle-free to use:
- the ECU controller mounts behind
the number plate for easy access
- accessing the ECU is accomplished simply by connecting
to a PC via the ECU controller using a USB cable (no
additional switches are necessary)
- setting adjustments can be prepared in advance on
a PC, or done when connected to the ECU
- the kit’s user-interface is simple to understand
and easy to use
The KX FI Calibration Kit contains seven preset settings
that can be quickly and easily used to adjust the
ECU to suit track conditions. The provided settings
are shown below.
- Richer fuel setting : fuelling 5%
richer than stock
- Leaner fuel setting : fuelling 5% leaner than stock
- Advanced ignition setting : ignition advanced 3Â°
- Retarded ignition setting : ignition retarded 3Â°
- Hard riding surface setting : ignition retarded,
- Soft riding surface setting : ignition advanced,
- Beginner setting : engine power suppressed: ignition
retarded, fuelling richer
For more advanced setting optimisation, the ECU maps
for volume of fuel injected (via the FI adjustment
window) and ignition timing (via the IG adjustment
window) can be adjusted for given throttle position
When connected to the ECU, the KX FI
Calibration Kit can be used to display the status
of a running engine. Information can be displayed
in numeric form using the Data Monitor, or in visual
form using the various display options offered by
the Data Meter.
The logged data can lined up with the
course layout to check actual riding, enabling more
efficient FI settings to be determined. It also enables
before-and-after comparisons and comparisons between
The 2012 kit is compatible with 64-bit operating systems
(such as Windows 7) as well as 32-bit systems (Windows
7, XP, Vista).
For more detailed information on use and functions
of the FI Calibration Kit, please refer to the KX
FI Calibration Kit Instruction Manual.
Tailor-fit ride position adjustability
Being comfortable on your bike is crucial
to delivering your best performance. Adjustable handle
and footpeg position allow riders to tailor their
riding position to suit body size and riding style.
Upper triple clamp with two sets of
handle mount slots and reversible handle mounts offer
riders a choice of four handle positions to choose
from: 25 mm FWD, 15 mm FWD, STD and 10 mm BK.
Adjustable footpeg brackets enable riders to lower
their footpeg position 5 mm. In the lower position,
CofG is lowered as is the rider’s point of view,
adding to both physical and psychological stability.
Using an optional rear suspension tie rod (1 mm longer
than normal), riders can lower their seat height by
4 mm (measured at the centre of the seat).
While 4 mm may not sound like much,
on a race bike being able to make ride position adjustments
without any compromise to riding performance is extremely
HARD-HITTING FUEL-INJECTED POWER
Fuel-injected 449 cm³ liquid-cooled,
4-stroke Single delivers hard-hitting power from lowthrough
high-rpm. The broad powerband and responsive throttle
offer a broad spread of torquey response that enables
racers to get on the gas and go even from down low.
In addition to the inherent benefits, fuel injection
contributes to the KX450F’s lag-free acceleration,
especially after landing jumps. Already featuring
race-inspired tuning and parts like the high-performance
piston with bridged-box bottom (a mass-production
introduced on the 2010 KX450F), for 2012 engine fine-tuning
and revised ECU settings offer increased performance
at both ends of the rev-range, resulting in a wider
powerband. Other changes contribute to improved shift
feel and throttle response.
Factory-racer engine tuning
High-performance piston, featuring
the same design used on our factory racers, contributes
to improved performance at all rpm. A short skirt,
reinforced external ribs and the industry’s
only mass-production use of a bridged-box bottom,
featuring fully flush internal bracing, result in
a lighter, stronger piston.
Idealised piston rigidity balance care of a reconfigured
bridge section contributes to increased mid-high rpm
A thinner top ring and revised surface treatment for
the oil ring reduce friction, contributing to increased
response at all rpm.
Revised intake cam profiles increase intake valve
lift (0.4 mm greater) enabling a greater volume of
air. This contributes to increased low-mid range performance.
At idling speed a smaller portion of intake air is
routed through the bypass circuit main bore, resulting
in improved response when first opening the
Wedge-shaped crank web increases offsetting moment
for a high crankshaft balance factor. At close to
60%, the balance factor of the ’12 KX450F is
on par with Ryan Villopoto’s factory racer.
The high balance factor contributes to reduced engine
vibration, smoother power delivery and increased performance
– especially at low rpm, where response is noticeably
In addition to generating the electrical output necessary
to ensure easy starting, the large-diameter ACG also
contributes to engine feeling at partial throttle.
Stainless steel header pipe is now tapered, contributing
to increased mid-high rpm performance.
Tapered joint pipe (between header and silencer) contributes
to increased performance at all rpm.
Improved shift feeling
To match the wider powerband, changes
to the transmission facilitate changing gears in the
high-rpm range. The changes also contribute to a significant
improvement in overall power feeling.
Increasing the number of engagement
dogs and slots (from 3 to 4) and revising the angles
of the dogs and
slots increases the chance of gear engagement. The
idealised amount of play also contributes to improved
Thicker 1st gear (9.2 mm > 12 mm) offers increase
Shorter shift fork stroke (5.3 mm >
4.4 mm) reduces the load when changing gears, contributing
to the improved shift feeling.
Battery-less fuel injection system
Designed specifically for motocrossers,
the fuel injection system incorporates a small lightweight
ECU and operates without a battery to further eliminate
unnecessary weight. And of course, fuel injection
eliminates the need to adjust engine settings to suit
track and climate conditions.
Ensuring quick starting without a battery
was a prime directive when developing the KX450F’s
fuel injection system. Using only electricity generated
by the kick starter, the engine can be started with
only three rotations of the crankshaft. The system
delivers electricity in the following order: 1) ECU,
2) fuel pump, 3) injector. With a warm engine, starting
can be accomplished in a single kick.
The compact, lightweight ECU, located just in front
of the steering head (behind the number plate), was
designed specifically for motocross use. To help cope
with the shocks and vibrations of motocross riding,
the fuel pump relay is built in to the ECU.
The 43 mm throttle body makes use of a progressive
throttle link to deliver airflow in much the same
way as would a FCR carburettor. Using two linked shafts,
the throttle body opens more quickly after the 3/8
open position, delivering sharp response and excellent
Ultra-fine atomising injector with 12 holes sprays
particles with a droplet size of 60 µm for smooth
power delivery and improved engine response at partial
The injector was set at 45°, the optimum angle
for improved mid-range power.
Lightweight flat-bottom aluminium fuel
pump is located in the plastic fuel tank.
To ensure a stable fuel supply during
vigorous motocross riding, the fuel pump features
a unitised plastic fuel
filter cover that wraps around the inlet port and
acts as a fuel trap. (Unitising the filter cover,
changing its material from rubber to plastic and eliminating
the fuel return hose from the pressure regulator contribute
to weight reduction.)
The Launch Control Mode indicator lamp will light
up to warn of a problem with the FI system.
Other performance-enhancing engine characteristics
The engine was tuned such 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.
The engine is almost upright (forward lean angle is
3°) to help place the bike’s centre of gravity
in the ideal position for maximum traction.
Asymmetrical high-acceleration cams yield high intake
During the cylinder head casting process,
the cores for the intake ports were given a special
coating to make the intake ports smoother. The extremely
smooth surfaces that result increase intake efficiency
at all rpm.
Lightweight titanium valves (IN: 36 mm; EX: 31 mm)
reduce reciprocating weight and offer high-rpm reliability.
Aluminium valve spring retainers reduce reciprocating
weight for reliable valve control at high-rpm.
Double valve springs also help ensure stable valve
operation and allow a short cylinder head height.
32 mm thick, 127.8 mm wide radiators with wide fin
and tube pitch offer resistance to mud build-up while
maintain cooling performance. The radiators are strong
enough that the reinforcing brackets could be eliminated,
resulting in lower overall weight.
Large openings in the radiator shrouds promote airflow,
contributing to cooling performance.
The screw-type adjuster on the cam chain tensioner
is equipped with a pressure spring. Because the system
automatically minimises the vibration caused by a
loose cam chain, it greatly reduces the chance of
a mishap during a race. (Non-automatic systems that
are tuned incorrectly can actually adversely affect
valve timing by
putting too much pressure on the cam chain.)
The combination of the smooth-shifting, close-ratio
5-speed transmission with the KX450F’s low-rpm
engine performance offers the rider the option to
shift to a higher gear when traversing rough sections.
This reduces the effect of sudden (unwanted) throttle
input, allowing focus to be given to racing rather
than careful throttle control.
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 KX450F is equipped with an
automatic compression release (ACR) system. The dual-weight
centrifugal decompression system fitted to the exhaust
cam eases starting in much the same way as a conventional
Sprocket-style chain drive roller helps smooth engine
braking by reducing the effect of driveline lash when
the rider gets off the gas quickly and play in the
lower side of the chain suddenly tightens. The additional
control facilitates corner entry.
FACTORY-STYLE CHASSIS COMPONENTS AND TUNING
The KX450F’s slim aluminium perimeter
frame is a lightweight construction composed of forged,
extruded and cast parts. Chassis balance and settings
were all set to suit race-experienced riders. The
centre of gravity and key dimensions (swingarm pivot,
output sprocket and rear axle locations) were chosen
so that the rear
tyre would drive the bike forward (instead of causing
it to squat). For 2012, a slimmer new frame, newly
designed minimalist bodywork, a thinner front tyre
and suspension fine-tuning offer lighter handling,
improved ergonomics and greater rear wheel traction.
As before, KX450F’s highly acclaimed high-speed
Minimalist bodywork (the shrouds and
side covers were made as small as possible) contributes
to a lower centre of gravity, making the bike easier
to throw around. The new parts are also lighter.
The fuel tank has a smaller volume (7.0 L > 6.2
L) and its top is 20 mm lower, both contributing to
the lower centre of gravity. The new tank is also
100 g lighter.
Narrower front tyre size (90/100-21 > 80/100-21)
contributes to lighter handling. The new tyre (same
as that used on the KX250F) is also 150 g lighter,
contributing to reduced unsprung weight.
Short-style silencer (60 mm shorter) contributes to
a more centralised mass, adding to the lighter
Superior rear wheel traction
Revised rigidity balance of the new
frame’s swingarm bracket area sees the upper
portion with fewer, thinner reinforcing ribs, and
a beefier lower portion with thicker ribbing. The
result is increased rear wheel traction and a more
solid feeling when landing jumps.
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.
Extensive rider testing was conducted to determine
the ideal linkage ratios and rear shock absorber damping
settings to achieve maximum rear wheel traction.
Rear suspension tie rod arms have less rigidity, resulting
in a smooth suspension action with firm feel that
contributes to the increased rear wheel traction.
KYB AOS (Air-Oil-Separate) fork keeps
oil and air in separate chambers for stable damping
performance during long motos. Low-friction fork seals
contribute to smooth action.
Revised clamps for the lower triple clamp open at
the back (previously on the side). The increased rigidity
contributes to improved fork action
A super-hard DLC coating (Diamond-Like Carbon) on
the outer surface of the inner fork tubes reduces
sliding friction (and stiction) and gives better action,
contributing to the smoother ride. The coating is
even effective when the fork is exposed to lateral
forces that would usually hamper slide action, such
during cornering. The increased surface hardness also
minimises scratches and damage to the tubes.
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.
The rear shock features dual compression adjustability,
allowing high-speed and low-speed damping to be tuned
The rear shock also features the Kashima Coat on the
tank cylinder. The reduced friction smoothes suspension
Front and rear suspension settings complement the
The new frame and minimalist bodywork,
designed with rider ergonomics in mind, offer a slimmer
rider interface and improved ergonomics. Complemented
by adjustable handle and footpeg positions, the natural
riding position makes it even easier for racers to
The new frame is 4 mm narrower (2 mm
each side) measured across the main pipes, contributing
to a slimmer package and to the improved ergonomics.
The slimmer riding position facilitates control.
With fuel tank volume reduced and the top of the tank
lower, the tank and seat form a straighter line. The
flatter design gives the rider greater freedom of
movement when changing riding position.
Minimalist shrouds are significantly smaller and are
slimmer where they come in contact with the rider’s
legs. 2-tone design was achieved using a double-injection
Minimalist side covers were also made as small as
Seat features a straight-line design.
New urethane helps maintain the original shape longer.
The seat uses a slip-resistant top surface for good
grip when seated and smooth sides for excellent rider
Seams between the shrouds, seat and side covers are
very flush, which facilitates control as well as moving
around on the bike.
The frame widens at the ankles to offer the rider
better grip and narrows near the bend below the seat
to allow a slim riding position.
Optimised exhaust pipe line also contributes to the
Wide (front-to-rear) footpegs designed
to offer grip and superb feel at the pegs. The clutch
cable boot features a large quick adjuster, making
it easier for riders to adjust play in the clutch
Throttle grip has a unitised collar. The one-piece
unit provides additional stability during throttle
Lightweight short-length grips feature a pattern designed
to provide excellent grip.
Other race-oriented chassis
The KX450F 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.
Rigid-mount front disc with an aggressive new petal
design reduces unsprung weight 80 g.
Rear caliper guard protects the caliper from damage.
A factory-style Renthal (standard-type)
aluminium handlebar is standard equipment.
Rib-less rear hub and butted spokes reduced unsprung
Front fender, shrouds, seat and rear
fender form a Lime Green “flow line”
Factory-style graphics complement the KX450F’s
highly tuned performance.
Rims are coated in black alumite1 –
just like our factory racers.
Fork and rear shock adjusters have a blue alumite1
finish like our US factory racers.
Blue finish on the oil cap and the
two plugs on the generator cover further contribute
to factory looks.
Embossed design on the clutch cover designed to gradually
appear as contact from riding boots wears off the
Fast-idle knob on the throttle body
allows riders to increase engine speed when first
starting a cold engine.
The crankshaft and connecting rod received a carburising
and quenching treatment for additional rigidity.
The camshaft lobes feature a soft-nitriding surface
treatment for long wear and high-rpm reliability.
Tappet surfaces receive a carburising treatment for
A large flap inside the air cleaner
case helps prevent the ingress of mud.
While the new silencer is 60 mm shorter,
its volume is the same (thanks to a revised cross-section),
ensuring noise regulations are met.
The silencer uses long-fibre packing which is much
more resistant to being blown out of the tail pipe
than standard length packing. As a result, packing
needs to be replaced half as often.
On European models, pinched cut-outs in the silencer
chambers direct exhaust gases into the glass-wool
packing, helping to reduce exhaust noise.
Clutch springs with a revised spring rate offer a
more direct feel, contributing to improved feeling.
Shift lever revised for greater durability.
Teeth on the kick start ratchet have
been redesigned to enable the lever to return to its
start position more smoothly after a kick.
The alloy swingarm uses a cast front
section, tapered hydroformed spars and forged chain
Large synthetic skid plate offers great protection
with minimum weight.
Optional engine parts include magneto
rotors with different inertias
Optional chassis parts include handlebar
holders for a ø28.6 mm bar (STD: ø22.2
mm), aluminium and steel rear sprockets (48-52T; STD:
50T), solid petal brake rotors for wet races, and
different springs for the front fork (4.6, 4.8 N/mm;
STD: 4.7 N/mm) and rear shock (52, 56 N/mm; STD: 54