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Standard Features


Prepare for Launch…

The race-winning power and confident handling of Kawasaki’s KX™450F motocrosser are back in an even sleeker and more advanced package than ever before. With racing always at the forefront, the KX450F’s latest technical innovations were developed from the factory know-how of the Monster Energy Kawasaki race team, with the final product representing an unmatched combination of cutting-edge innovation and race-proven components. Its best-in-class performance is facilitated by the highest level of rider adjustability and the most progressive electronics package ever seen on a production motocrosser. From the moment the gate drops, the 2012 KX450F is set to leave challengers in its dust.


Model Year
Starting at MSRP


85.8 in.
50.2 in.
32.3 in.
249.1 lbs.
Ground Clearance
13 in.
58.3 in.
Seat Height
37.6 in.


4-stroke single, DOHC, 4-valve cylinder head
449 cc
Bore x Stroke
96 x 62.1 mm
Compression Ratio
Fuel System
43 mm Keihin throttle body
Fuel Tank Capacity
1.64 gal.
Digital DC-CDI




Front: Single 250 mm petal disc with 2-piston caliper
Rear: Single 240 mm petal disc with 1-piston caliper
Front: 80/100-21
Rear: 120/80-19


UNI-TRAK® linkage system and Kayaba shock with 50 mm piston, 22-position low-speed and stepless high-speed compression dampening, 22-position rebound dampening and fully adjustable spring preload; 12.4 in. travel
4.4 in.


Lime Green

Standard Features

Key Features
 All-new Launch Control Mode increases the chance of nailing the holeshot  
 New pre-programmed ignition maps, interchangeable trackside, no PC required  
 Upgraded engine with more top-end thrust and a wider powerband  
 New adjustable bar and footpeg positions  
 New slimmer frame and minimalist bodywork  
 Upgraded transmission for easy, reliable shifting  
 New pipe and silencer help centralize mass  
 50 mm AOS forks with DLC coated inner fork tubes  
 Black Alumite coated rims  
Engine Overview
 449 cc liquid-cooled, DOHC, 4-stroke single  
 Works-based Bridged-box Bottom Piston has revised rigidity for improved high-rpm power  
 Revised intake cam and all-new exhaust result in wider powerband  
 A forward lean angle of 3° puts the engine in the ideal position for maximum traction  
 Highly balanced crankshaft, on par with Villopoto’s factory racer, creates minimal vibration  
 Maintenance-free automatic cam chain adjuster  
 Large airbox flap helps prevent mud and water from entering  
Bridged-box Bottom Piston
 Thinner top ring and revised surface treatment of oil ring reduce friction  
 Same design as used on our factory racers; offers optimum performance at all rpm  
 Lighter and more durable than traditional piston designs  
 Short piston skirt features low-friction coating to minimize mechanical losses  
 Reinforced external ribs enhance strength and durability  
Cylinder Head
 Compact head is only 100 mm tall  
 Intake camshaft profile revised to increase intake for better low- and mid-range power  
 36 mm titanium intake and 31 mm exhaust valves with aluminum spring retainers minimize reciprocating weight and cylinder height to help ensure reliable valve control at high rpm  
 Double valve springs allow a short cylinder head height and help ensure stable valve operation  
 Camshafts, lobes and tappet surfaces feature a soft-nitride treatment for long wear and high-rpm reliability  
 Crankshaft with high inertial mass helps maximize rear wheel traction  
 Wedge-shaped crank web provides enough offsetting moment for a 60% balance factor – and is similar to the crank balance in Kawasaki’s factory race engines  
 Net result is reduced engine vibration, smoother power delivery and increased performance, with a noticeably snappier response at low rpm  
 Crankshaft and connecting rod feature a special carburizing and quenching treatment to maximize rigidity  
Digital Fuel Injection
 Self-adjusts to atmospheric changes for easier starting, sharper throttle response and optimized power and stability when jumping / landing  
 It is not necessary to re-tune, or change any jets to suit climatic conditions like on a carbureted model  
 Ultra-fine atomizing injector with 12 holes sprays particles with a droplet size of 60µ for smooth power delivery and engine response throughout the throttle range  
 43 mm 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  
 Fast-idle knob on the throttle body allows riders to increase engine speed when starting a cold engine  
 Fuel injector set at 45°, the optimum angle for mid-range power  
Launch Control Mode
 Factory-style launch control system increases chance of getting a good start by maximizing traction on a slippery surface  
 Push-button activation of the Launch Control Mode retards ignition timing in 1st and 2nd gears, giving the greatest effect within the first few seconds of releasing the clutch  
 Launch Control can be activated in neutral, 1st or 2nd gear  
 Shifting into 3rd gear deactivates Launch Control Mode and returns the ignition to normal mapping  
 System is designed to same specifications as factory Kawasaki AMA machines  
High Performance ECU
 New ECU programming offers three preprogrammed maps: Standard, Hard (conditions) and Soft (conditions)  
 Maps are now easily selectable via DFI wire coupler caps, no computer necessary  
 No battery needed; 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: first the ECU, then the fuel pump, and finally the injector for quick, easy starting  
 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 integrated with the ECU to help cope with the shocks and vibrations of motocross riding  
Optional User ECU Setting Tool
 KX 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 preference  
 The tool can also be used as a data logger, recording up to 6 hours of data, including engine rpm, degree of throttle opening, engine boost, coolant temp, air temp, ignition timing, fuel adjustments, gear position and system voltage  
 2012 software program is updated for compatibility with 64-bit operating systems such as Windows 7  
Easy Starting
 Revised shape of kickstart ratchet enables lever to return to start position more smoothly  
 Strong output from the large ACG rotor provides enough electrical power for the battery-less FI system to enable true 1-kick starting without using a battery  
 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  
 Compression release features 1 mm of valve lift, to minimize the required kicking power  
Lightweight Aluminum Fuel Pump
 Fuel pump now features a 1-piece filter cover and body, eliminating the need for fuel return tube from pressure regulator and contributing to weight reduction  
 Features 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 riding  
 New 1.6 gal. fuel tank is formed using a blow molding process  
Efficient Cooling
 High-capacity Denso radiators feature tightly packed cores and a fin design that deliver superior cooling efficiency  
 Changed left side radiator upper pipe angle for new shroud design  
 New shroud shape features a slimmer profile and larger cooling outlet hole  
 Radiator louvers feature 4 small blades set at a shallow angle for minimum overlap and maximum air flow  
Strong and Durable Clutch
 Clutch assembly provides a direct feel and superb control  
 Heavier clutch springs give a more positive feel to the rider  
 Excellent oil drainage contributes to more direct feel  
 Friction plates with substantial friction material contribute to a direct feel  
 New clutch case cover features embossed logo, designed to be revealed as rider’s boot wears away black paint  
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  
 Revised number of gear dogs (3 dogs / 3 holes to 4 dogs / 4 holes) improve shift feel  
 Thicker first gear offers greater durability for launching off the line  
 Shorter shift fork (5.3 mm to 4.4 mm) reduces the shift force necessary to change gears  
 New shift lever moves the pedal 3 mm farther from the footpeg and offers greater durability  
 New polyurethane resin drive chain roller reduces weight  
 New tapered header pipe is shorter in length and features a smaller overall diameter  
 Tapered mid-piece is new for 2012 KX450F  
 New silencer is 60 mm shorter, but thanks to a new cross-section, features same overall volume as 2011 model to help meet current 94 dB noise regulations  
Powerful Disc Brakes
 New front disc features an aggressive petal design  
 Powerful twin piston hydraulic front caliper squeezes 250 mm rotor  
 Lightweight rigid-mounted front disc reduces unsprung weight by 80 g  
 Single piston hydraulic rear caliper squeezes lightweight 240 mm petal-type rotor  
Light, Slim Chassis
 New main frame spars are 4 mm slimmer to help reduce overall width at the rider’s knees  
 Increased rigidity in the swingarm bracket area helps increase rear wheel traction and provide a more solid feel when landing jumps  
Aluminum Swingarm
 Cross-section design contributes to light handling  
 Tapered “D” shape swingarm provides ideal rigidity for excellent stability, and is lighter than a comparable box-section unit  
 Alloy swingarm features a cast front section, tapered hydro-formed spars and forged chain adjusters  
 Uni-Trak® rear suspension linkage altered for improved traction, utilizing a revised tie-rod unit which is less rigid  
 Suspension arm is mounted below the swingarm to allow a longer rear suspension stroke and more precise tuning  
 New optional linkage tie rod is 1mm shorter, creating a 6 mm reduction in seat height for shorter riders  
AOS Front Fork
 Race-oriented suspension settings offer maximum overall performance  
 Revised lower triple clamp locates the clamp opening in the rear as opposed to the side for increased rigidity and improved fork action  
 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  
 Diamond-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 cornering  
 Friction-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 feel  
 Wrap-around fork tube guards offer effective protection for the sliders  
Rear Shock
 Rear suspension settings and linkage ratios derived from extensive rider testing  
 Kayaba rear shock features a large 50 mm piston  
 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  
 Easy adjuster access for track-side suspension tuning  
Rider Interface and Styling
 Dual injected 2-tone, 1-piece plastic shrouds and side number plates minimized for mass centralization and rider comfort  
 Upgrades bodywork features more flush seams for easier rider movement  
 Lower-capacity fuel tank is shorter and narrower, creating a straighter line from the seat  
 Black plastic covers, triple clamps, engine covers, and black alumite-coated rims – just like Kawasaki’s factory teams  
 Blue alumite finish on suspension adjusters and engine plugs match new graphics accents  
 Wide 50 mm footpegs can be adjusted to alternate position, 5 mm lower than stock  
 Frame is wider at the ankles to offer optimum grip, narrows below the seat to allow a slim riding position  
 Slim seat design uses new urethane foam designed to retain its original shape longer  
Additional Features
 Skid plate made of resin material offers great protection without excess weight  
 Clutch cable boot features a large quick adjuster, making it easy for riders to adjust play in the clutch cable on the fly  
 Rear caliper guard helps protect the caliper from damage  
 Ribless rear hub and butted spokes offer light weight and excellent durability  


Lime Green
*Price, if shown, is Manufacturer's Suggested Retail Price (MSRP) and does not include government fees, taxes, dealer freight/preparation, dealer document preparation charges or any finance charges (if applicable). MSRP and/or final actual sales price will vary depending on options or accessories selected.

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*Suggested Retail Price (SRP) excludes destination charge. Visit to view applicable destination charge amount.

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