At A Glance...All-new Launch Control Mode increases the chance of nailing the holeshotNew pre-programmed ignition maps, interchangeable trackside, no PC requiredUpgraded engine with more top-end thrust and a wider powerbandNew adjustable bar and footpeg positionsNew slimmer frame and minimalist bodyworkUpgraded transmission for easy, reliable shiftingNew pipe and silencer help centralize mass50mm AOS forks with DLC coated inner fork tubesBlack Alumite coated rimsEngine Overview449cc liquid-cooled, DOHC, four-stroke singleWorks-based Bridged-box Bottom piston has revised rigidity for improved high-rpm powerRevised intake cam and all-new exhaust result in wider powerbandA forward lean angle of 3° puts the engine in the ideal position for maximum tractionHighly balanced crankshaft, on par with Villopoto's factory racer, creates minimal vibrationMaintenance-free automatic cam chain adjusterLarge airbox flap helps prevent mud and water from enteringBridged-Box Bottom PistonThinner top ring and revised surface treatment of oil ring reduce frictionSame design as used on our factory racers; offers optimum performance at all rpmLighter and more durable than traditional piston designsShort piston skirt features low-friction coating to minimize mechanical lossesReinforced external ribs enhance strength and durabilityCylinder HeadCompact head is only 100mm tallIntake camshaft profile revised to increase intake for better low and mid-range power36mm titanium intake and 31mm exhaust valves with aluminum spring retainers minimize reciprocating weight and cylinder height to help ensure reliable valve control at high rpmDouble valve springs allow a short cylinder head height and help ensure stable valve operationCamshafts, lobes and tappet surfaces feature a soft-nitride treatment for long wear and high-rpm reliabilityCrankshaftCrankshaft with high inertial mass helps maximize rear wheel tractionWedge-shaped crank web provides enough offsetting moment for a 60 percent balance factor – and is similar to the crank balance in Kawasaki's factory race enginesNet result is reduced engine vibration, smoother power delivery and increased performance, with a noticeably snappier response at low rpmCrankshaft and connecting rod feature a special carburizing and quenching treatment to maximize rigidityDigital Fuel InjectionSelf-adjusts to atmospheric changes for easier starting, sharper throttle response and optimized power and stability when jumping/landingIt is not necessary to re-tune, or change any jets to suit climatic conditions like on a carbureted modelUltra-fine atomizing injector with 12 holes sprays particles with a droplet size of 60µ for smooth power delivery and engine response throughout the throttle range43mm throttle body uses a progressive throttle linkage to deliver airflow in much the same way as an FCR carburetorUsing two linked shafts, the throttle body opens more quickly after reaching the 3/8 open positionFast-idle knob on the throttle body allows riders to increase engine speed when starting a cold engineFuel injector set at 45°, the optimum angle for mid-range powerLaunch Control ModeFactory-style launch control system increases chance of getting a good start by maximizing traction on a slippery surfacePush-button activation of the Launch Control Mode retards ignition timing in first and second gears, giving the greatest effect within the first few seconds of releasing the clutchLaunch Control can be activated in neutral, first or second gearShifting into third gear deactivates Launch Control Mode and returns the ignition to normal mappingSystem is designed to same specifications as factory Kawasaki AMA machinesHigh Performance ECUNew ECU programming offers three preprogrammed maps: Standard, Hard (conditions) and Soft (conditions)Maps are now easily selectable via DFI wire coupler caps, no computer necessaryNo battery needed; the engine can be started with only three rotations of the crankshaft using the electricity generated by a single kick of the starterThe system delivers electricity to FI system in sequence: first the ECU, then the fuel pump, and finally the injector for quick, easy startingThe 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 integrated with the ECU to help cope with the shocks and vibrations of motocross ridingOptional User ECU Setting ToolKX FI Calibration Kit allows racers to reprogram the ECU's data maps for volume of fuel injected and ignition timing to alter engine characteristics to suit rider preferenceThe tool can also be used as a data logger, recording up to six hours of data, including engine rpm, degree of throttle opening, engine boost, coolant temp, air temp, ignition timing, fuel adjustments, gear position and system voltage2012 software program is updated for compatibility with 64-bit operating systems such as Windows 7Easy StartingRevised shape of kickstart ratchet enables lever to return to start position more smoothlyStrong output from the large ACG rotor provides enough electrical power for the battery-less FI system to enable true one-kick starting without using a batteryEquipped with an automatic compression release (ACR) system for quick and easy starting. The dual-weight centrifugal decompression system is fitted to the exhaust camCompression release features 1.0mm of valve lift, to minimize the required kicking powerLightweight Aluminum Fuel PumpFuel pump now features a one-piece filter cover and body, eliminating the need for fuel return tube from pressure regulator and contributing to weight reductionFeatures a plastic (formerly 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 ridingNew 1.6-gallon fuel tank is formed using a blow molding processEfficient CoolingHigh-capacity Denso radiators feature tightly packed cores and a fin design that deliver superior cooling efficiencyChanged left side radiator upper pipe angle for new shroud designNew shroud shape features a slimmer profile and larger cooling outlet holeRadiator louvers feature four small blades set at a shallow angle for minimum overlap and maximum air flowStrong and Durable ClutchClutch assembly provides a direct feel and superb controlHeavier clutch springs give a more positive feel to the riderExcellent oil drainage contributes to more direct feelFriction plates with substantial friction material contribute to a direct feelNew clutch case cover features embossed logo, designed to be revealed as rider's boot wears away black paintClose-Ratio 5-Speed Transmission5-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 racingRevised number of gear dogs (3 dogs/3 holes to 4 dogs/4 holes) improve shift feelThicker first gear offers greater durability for launching off the lineShorter shift fork (5.3mm to 4.4mm) reduces the shift force necessary to change gearsNew shift lever moves the pedal 3mm farther from the footpeg and offers greater durabilityNew polyurethane resin drive chain roller reduces weightExhaustNew tapered header pipe is shorter in length and features a smaller overall diameterTapered mid-piece is new for 2012 KX450FNew silencer is 60mm shorter, but thanks to a new cross-section, features same overall volume as '11 model to help meet current 94dB noise regulationsPowerful Disc BrakesNew front disc features an aggressive petal designPowerful twin piston hydraulic front caliper squeezes 250mm rotorLightweight rigid-mounted front disc reduces unsprung weight by 80 gramsSingle piston hydraulic rear caliper squeezes lightweight 240mm petal-type rotorLight, Slim ChassisNew main frame spars are 4mm slimmer to help reduce overall width at the rider's kneesIncreased rigidity in the swingarm bracket area helps increase rear wheel traction and provide a more solid feel when landing jumpsAluminum SwingarmCross-section design contributes to light handlingTapered “D” shape swingarm provides ideal rigidity for excellent stability, and is lighter than a comparable box-section unitAlloy swingarm features a cast front section, tapered hydroformed spars and forged chain adjustersUni-Trak® rear suspension linkage altered for improved traction, utilizing a revised tie-rod unit which is less rigidSuspension arm is mounted below the swingarm to allow a longer rear suspension stroke and more precise tuningNew optional linkage tie rod is 1mm shorter, creating a 6mm reduction in seat height for shorter ridersAOS Front ForkRace-oriented suspension settings offer maximum overall performanceRevised lower triple clamp locates the clamp opening in the rear as opposed to the side for increased rigidity and improved fork actionKayaba 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 actionDiamond-Like Carbon (DLC) coating on the outer surface of the inner fork tubes offers minimum stiction when the fork is exposed to lateral forces that would usually hamper slide action. The result is improved fork response, especially during corneringFriction-reducing Kashima Coat on the inside of the fork's outer tubes contributes to smooth suspension action (especially at the initial part of the stroke) and a superb ride feelWrap-around fork tube guards offer effective protection for the slidersRear ShockRear suspension settings and linkage ratios derived from extensive rider testingKayaba rear shock features a large 50mm pistonRear shock features dual compression adjustability, allowing high-speed and low-speed damping to be tuned separatelyAlso features Kashima Coat treatment on the cylinder for reduced friction and smoother suspension actionEasy adjuster access for track-side suspension tuningRider Interface and StylingDual injected 2-tone, one-piece plastic shrouds and side number plates minimized for mass centralization and rider comfortUpgrades bodywork features more flush seams for easier rider movementLower-capacity fuel tank is shorter and narrower, creating a straighter line from the seatBlack plastic covers, triple clamps, engine covers, and black alumite-coated rims – just like Kawasaki's factory teamsBlue alumite finish on suspension adjusters and engine plugs match new graphics accentsWide 50mm footpegs can be adjusted to alternate position, 5mm lower than stockFrame is wider at the ankles to offer optimum grip, narrows below the seat to allow a slim riding positionSlim seat design uses new urethane foam designed to retain its original shape longerAdditional FeaturesSkid plate made of resin material offers great protection without excess weightClutch cable boot features a large quick adjuster, making it easy for riders to adjust play in the clutch cable on the flyRear caliper guard helps protect the caliper from damageRibless rear hub and butted spokes offer light weight and excellent durabilitySpecificationsEngine: Liquid-cooled, four-stroke single with DOHC and four-valve cylinder headDisplacement: 449ccBore x stroke: 96.0 x 62.1mmCompression ratio: 12.5:1Fuel System: 43mm Keihin throttle bodyIgnition: Digital DC-CDITransmission: Five-speedRake / trail: 26.9 degrees / 4.4 in.Rear suspension / wheel travel: Uni-Trak® linkage system and Kayaba shock with 50mm piston, 22-position low-speed and stepless high-speed compression dampning, 22-position rebound dampening and fully adjustable spring preload / 12.4 in.Front tire size: 80/100-21Rear tire size: 120/80-19Front brakes: Single 250mm petal disc with dual piston caliperRear brakes: Single 240mm petal disc with single-piston caliperOverall length: 85.8 in.Overall width: 32.3 in.Overall height: 50.2 in.Wheelbase: 58.3 in.Ground clearance: 13.0 inSeat height: 37.6 in.Curb weight: 249.1 lbs.Fuel capacity: 1.64 gal.Color Choices: Lime Green