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2012 Kawasaki KX450

2012 Kawasaki KX450


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 podium finishers.

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 ECU
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.


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 engine map
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 lines.)

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 engine map.

(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 Kit (option)

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 settings.

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 3° from stock
- Retarded ignition setting : ignition retarded 3° from stock
- Hard riding surface setting : ignition retarded, fuelling richer
- Soft riding surface setting : ignition advanced, fuelling leaner
- 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 and rpm.

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 riders.

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 beneficial.


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 first when
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 intake
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 snappier.

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 shift feeling.

Thicker 1st gear (9.2 mm > 12 mm) offers increase durability.

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 power feeling.

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 throttle.

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 efficiency.

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 lever-type system.

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.


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 stability
remains unchanged.

Lighter handling

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
handling characteristics.

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.

Race-oriented suspension

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 as
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 separately.

The rear shock also features the Kashima Coat on the tank cylinder. The reduced friction smoothes suspension action.

Front and rear suspension settings complement the new frame.

Rider interface

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 go fast.

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 moulding process.

Minimalist side covers were also made as small as possible.

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 mobility.

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 racer-friendly ergonomics.

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 cable.

Throttle grip has a unitised collar. The one-piece unit provides additional stability during throttle operation.

Lightweight short-length grips feature a pattern designed to provide excellent grip.

Other race-oriented chassis components

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 weight.

Factory styling

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 black paint.


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 increased durability.

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 adjusters.

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 N/mm).