First Look | 2015 Kawasaki KXF Line

2015 Kawasaki KX450F

It’s no secret that Monster Energy Kawasaki has been dominating the AMA Supercross and AMA Motocross series, with Ryan Villopoto piloting his Monster Energy® Kawasaki KX450F race bike to four consecutive AMA Supercross Championships in 2011 through 2014. Villopoto’s skills are undeniable, but the race-ready Kawasaki KX450F allows the legendary racer to brake later, carve deeper and accelerate harder thanks to a technology package and powerful yet tractable motor unrivaled by any production motocross bike.

2015 sees the KX450F rise to another level with greater rider adjustability along with chassis, suspension and brake upgrades aimed at maximizing performance for a variety of riders in most every condition. This ensures it is now easier than ever to access the performance of the KX450F and tailor it to fit the rider’s needs.


• Showa SFF-Air TAC Fork with Triple Air Chamber
• High-pressure 300psi digital air pump provided with every purchase
• Uni-Trak® with SHOWA shock
• Larger 270mm “oversize” Braking front disc, and 240mm rear
• Revised Bridged Box piston and ECU programming


What hasn’t been said about the legendary 450cc motor in the KX450F? It’s powerful, tractable and reliable, yet Kawasaki took it upon itself to also improve its design with a revised Bridged Box piston for increased durability and a high compression ratio (12.8:1 from 12.5:1 in 2014). The cutting edge piston design was pulled straight from the factory racer team and features short skirts with reinforced external ribs to improve combustion efficiency and reliability. It provides a stronger mid-range hit as well as a stronger feeling at high RPM.

From the saddle, the rider will experience the proven top-end and over-rev performance that the KX450F is known for, while maintaining its impressive torque. This championship-winning powerplant develops massive torque from the low revs and continues to pull all the way through the mid- and upper-range of the power curve like no other engine in history.

Of course, the revolutionary DFI® Couplers (Standard, Hard, Soft) are still utilized on the DFI system, allowing riders to change the fuel injection mapping in a matter of seconds to suit a variety of riding conditions. Easy access to the DFI coupler cap means no additional accessories are needed to alternate between pre-preprogrammed maps. The rider simply connects the appropriate coupler cap to immediately activate an ignition mode that matches local track conditions.
The ECU system was revised for 2015 with new programming to enhance traction by retarding the ignition when rear-wheel speed increases too quickly (from sudden, excess wheelspin).

The ECU is also fully re-programmable. Custom maps can be created using the optional accessory Kawasaki Racing Software Kit giving riders total power adjustability. This is the same tool used by Kawasaki factory and privateer teams in AMA and FIM racing.

The industry-first factory Launch Control System also remains for 2015, helping to ensure hole-shot supremacy. The push-button activation retards ignition timing in first and second gears, which, in turn, maximizes traction. Once the rider shifts into third, normal ignition mapping is resumed and full power returns.


An engine like this requires the grip and ride quality to match, and this is delivered by the upgraded suspension components for 2015. A high-tech Showa Separate Function Fork (SFF) with a Triple Air Chamber (TAC) separates the damping forces into the left fork tube, while the pneumatic spring is housed on the right tube for less friction, better movement and a lighter fork.

The innovative SFF-Air TAC fork is derived directly from Villopoto’s race bike and is revolutionizing the motocross market with better small- and large bump absorption, increased adjustability and superior reliability compared to conventional dual-spring forks.

The reduced weight and inertia of the pneumatic spring keeps the wheel in contact with the terrain thanks to very little resistance during rebound compared to conventional spring forks. These high-tech forks are also suppler over small bumps, while offering more resistance to bottoming.

As its name suggests, the Triple Air Chamber features three separate chambers with individual air volumes that allow the ultimate in adjustability, thanks to individual tuning. An inner 145psi high-pressure pneumatic chamber works in harmony with a 7.25psi low-pressure outer chamber and a 130.5psi high-pressure lower chamber. These replace the heavy, friction-inducing spring for the ultimate in function and tuning.

There is also less oil contamination from the metal-on-metal wear suffered by conventional internal fork springs. A titanium coating on the inner tubes improves fork action with diminished friction, and the silver external finish is factory fresh.

Suspension tuning with the Showa SFF-Air TAC is easier than ever thanks to the Kawasaki Genuine Accessories 0-300psi Digital Air Pump that is included with every KX450F. The Digital Air Pump makes life easier and helps riders quickly adjust the high-pressure SFF-Air TAC forks.

The digital display offers increased precision when setting air pressures, and the casing stores DFI Couplers for the fuel injection system for better organization on race day.

Out back, the Showa shock with Uni-Trak linkage has revised valving for stronger damping. This results in improved high-speed handling, greater stability and improved performance when landing. The race-oriented rear suspension offers class-leading action and adjustability that is on par with the matching Showa SFF-Air TAC up front.

The suspension is finished in “works black” for a race-ready style as competent as its performance. The Kashima coating inside the shock body reduces friction and improves suspension action. The fully adjustable unit allows for precise adjustments to help keep the rear wheel planted and the rider out front.
For ultra-competitive riders who are always looking for an extra edge over the competition, Kawasaki offers an optional rear suspension tie rod that is 1mm longer than stock. This simple yet effective modification can be used to reduce seat height by 4mm to give the rider greater control and adjustment.


A fast engine isn’t the only key to winning races. Being able to effectively enter every corner from speed is also critical. And Kawasaki upped the ante for 2015 with a new, oversized, petal-shaped front brake rotor from the renowned Braking company that increases stopping effectiveness, lever feel and consistency in all conditions.

Braking is known for its innovations in the motocross brake market, and its products have made their way onto the 2015 KX450F to give the rider the ultimate control and feel. The first WAVE® disc was developed and sold by Braking in 2000, and these new “petal” rotors are a testament to how far the technology has come in a relatively short amount of time.

The larger 270mm front rotor was increased from last year’s 250mm part. It is paired with a petal-shaped 240mm Braking rear rotor to give riders the ultimate feedback.

The petal-shaped rotors shed even the thickest of mud, allowing riders to reach the limits of adhesion without fear of locking, maintaining the ultimate in communication between the tire and rider. As any racer knows, better braking translates into quicker lap times.


World-class suspension components are not effective without proper support, so Kawasaki’s engineers worked hard to improve handling and chassis feedback with tweaks to the auxiliary components supporting the slim aluminium perimeter frame.

A new lighter rear subframe is shared with the lightweight KX250F, reducing the weight and improving mass centralization for quicker handling and a more nimble feel in the saddle – greater parts communization also means less out-of-pocket expenses for riders at the parts counter.

The alloy swingarm, with its cast front section, twin tapered hydro-formed spars in raw aluminum finish, and forged chain adjusters are fitted with a self-locking rear axle nut. The design holds the 80 lb ft torque setting without the need of a cotter pin, providing more precise torque settings and ease of maintenance. Small improvements like this will make pit work easier for grassroots racers and track junkies alike.

The axles are new for 2015, lightened by 31 grams front and 32 grams rear as a further weight saving measure to improve the overall feel.

Kawasaki’s commitment to riders continues with adjustable footpegs and handlebars to fit various sizes and riding styles. The footpegs feature dual-position mounting points, while the multi-position handlebars feature four individual settings and offset clamps to suit riders of many sizes.

Sparing no attention to detail, the seams between the radiator shrouds, seat and side covers are flush fitting. This helps avoid gear snags and allow the rider to change position and maneuver more freely on the bike. The compact fuel tank also forms a smooth straight line with the seat, allowing maximum rider movement.


The 2015 KX450F looks the part thanks to its enhanced styling that features a Lime Green finish with factory-style graphics. The appearance is further highlighted with green engine plugs, oil cap and generator cover plugs, as well as green alumite suspension adjusters and black alumite wheels. The coated components not only look at home in the pits, but the durable finish is corrosion and scratch-resistant.

Thanks to further refinement to an already class-leading performer, it’s easy to see why the 2015 KX450F will continue its success on podiums across the country, thanks to a proven pedigree and Kawasaki’s steadfast commitment to excellence and improvement.

For more information, visit and your local dealership.

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2015 Kawasaki KX450F

Features and Benefits

At a glance…

–      Launch Control helps to reduce wheelspin on slippery starting gates

–      Showa SFF-AIR fork with triple air chamber uses air to reduce weight, compared to traditional metal-coil fork springs, providing effective tuning and bottoming resistance

–      Includes a free electronic Kawasaki Genuine PSF Air Fork Pump and removable adjustment valve for quick and easy tuning of fork spring pressure

–      Engine is tuned for optimum power delivery all the way from basement revs through the upper RPM range, this results in impressive thrust that continues from corner-exit to the end of the straights

–      Revised Bridged Box piston. Piston crown allows for superior ultra-low to mid-range engine response

–      Intake cam shape promotes strong low-RPM throttle response

–      Larger 270mm “oversize” Braking petal-shape front disc, 240mm petal-shape rear disc

–      Front master cylinder features a knocker-style lever-to-piston interface for excellent feel and superbly consistent performance

–      Pre-programmed ignition maps are interchangeable trackside, no PC required

–      Adjustable 4-position handlebar and 2-position footpegs allow riders to fit the KX to match their personal preference

–      Black anodized aluminum rims for a factory look 

Engine Overview

–      449cc, liquid-cooled, DOHC, four-stroke single with legendary Kawasaki power!

–      Works-based bridged-box bottom piston has optimum rigidity for maximum high-rpm power and durability

–      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 and has a high inertial mass to help maximize rear wheel traction

–      Compact cylinder head is only 100mm tall

–      Double valve springs help ensure stable valve operation and also allow for a short cylinder head height

–      Camshafts, lobes and tappet surfaces feature a soft-nitride treatment for long wear and high-rpm reliability

–      Automatic cam chain adjuster is maintenance-free

–      Crankshaft and connecting rod feature a special carburizing and quenching treatment to maximize rigidity, boosting long-term reliability without adding weight

Digital Fuel Injection

–      Digital Fuel Injection (DFI®) self-adjusts to atmospheric changes for easier starting, sharper throttle response and accessible power for jumping

–      It is not necessary to re-tune or change any jets to suit climatic conditions like carbureted models

–      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

–      43mm 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

High-performance Multi-map ECU

–      Ignition timing boosts response when re-opening the throttle after deceleration (when landing jumps, etc.)

–      ECU programming is easily selectable via interchangeable DFI coupler caps that provide three preprogrammed maps for standard, hard (terrain) and soft (terrain), without the need for a  separate programmer or laptop

–      The engine can be started with only three rotations of the crankshaft using the electricity generated by a single kick of the starter, no battery needed

–      The system delivers electricity to the bike’s electronics 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 tough racing

Launch Control Mode

–      Factory-style launch control system is an industry first and increases the ability to get good starts by maximizing available traction

–      Push-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 clutch

–      Launch Control can be activated in neutral, first or second gear

–      Shifting into third gear automatically deactivates Launch Control Mode and returns the ignition to normal mapping

Easy Starting

–      Strong 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 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 1.0mm of valve lift, to minimize the required kicking power

Bridged-Box Bottom Piston

–      Piston crown shape tuned for excellent low to mid-range engine response

–      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

Showa SFF-AIR Front Fork

–      Showa SFF-AIR fork with triple air chamber uses air as a spring. The reduced weight and inertia of the air spring improves smoothness and enhances the fork’s ability to follow terrain contours

–      Air spring significantly reduces friction and cuts weight while also providing better bottoming resistance, less oil contamination, plus easier and more effective tuning compared to traditional springs

–      Large diameter internal damping cartridges help provide consistent performance and bottoming resistance

–      A removable spring pressure adjustment valve and free 0-300psi electronic Kawasaki Genuine Air Fork Pump are included for quick and easy tuning of fork spring pressure

–      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)

–      Wrap-around fork tube guards offer effective protection for the sliders

–      Lower triple clamp features integrated locating pins to help simplify installation and removal of the front number plate

–      One-piece front fender attachment screws feature integrated grommets to simplify installation and removal

Rear Shock

–      22-position rebound damping adjuster allows precise fine-tuning of the rebound circuit

–      Easy adjuster access allows track-side suspension tuning with a minimum of hassle or lost time

–      Rear shock features dual compression adjustability, allowing 19-position low-speed and 4 turns of high-speed damping adjustments to be made independently

–      Showa rear shock features a large piston and a Kashima coat treatment on the cylinder wall for reduced friction and smoother suspension action

Aluminum Swingarm

–      Tapered “D” shape swingarm is lighter than a comparable box-section unit and provides superior rigidity for its weight

–      Features tapered hydroformed spars and forged chain adjusters

–      Uni-Trak® rear suspension linkage is mounted below the swingarm to allow precise tuning and maximum rear suspension stroke

Fuel Tank and Lightweight Aluminum Fuel Pump

–      Compact 1.6-gallon fuel tank is formed using a blow molding process

–      Fuel pump features a one-piece filter cover and body, eliminating the need for fuel return tube from pressure regulator

–      Features a plastic 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

Efficient Cooling

–      High-capacity Denso radiators feature tightly packed cores and a fin design that deliver superior cooling efficiency

–      Shroud shape features a slim profile and large cooling outlet hole to help keep excess heat to a minimum

–      Radiator louvers feature four 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 of engagement

–      Excellent oil drainage reduces power loss caused by excess oil around the clutch basket

–      Friction plates with substantial friction material contribute to fade resistance and long service life

–      Clutch case cover features embossed logo and is painted silver, making scuffs and normal wear less noticeable

Close-ratio 5-Speed Transmission

–      5-Speed transmission and the engine’s broad torque curve gives riders more gear options for maximum drive on a wide range of tracks

–      Thick first gear offers excellent durability for launching off the line in high-traction situations

Powerful Disc Brakes

–      Front master cylinder features a knocker-style lever-to-piston interface for excellent feel and superbly consistent performance

–      Front brake pads offer a strong braking force and feel

–      Lightweight 270mm “oversize” Braking front rotor is squeezed by a powerful twin-piston caliper and features an aggressive petal design to help clear mud and debris

–      Lightweight 240mm Braking petal-type rear rotor features the same aggressive petal style as the front rotor and is gripped by a single piston hydraulic rear caliper

Rider Interface and Styling

–      Slender frame helps the bike feel compact and nimble, but tapers to become wider near the rider’s ankles to offer optimum grip and control

–      Wide 50mm footpegs can be adjusted to alternate position, 5mm lower than stock

–      Dual injected 2-tone, one-piece plastic shrouds and side number plates are great looking, compact and lightweight

–      Black triple clamps and black anodized rims – just like Kawasaki’s factory teams

–      Blue finish on suspension adjusters and engine plugs look like the factory race parts

–      Slim seat design uses urethane foam designed to retain its original shape and provide optimum durability

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 clutch play on the fly

–      Rear caliper guard helps protect the caliper from damage

–      Ribless rear hub and butted spokes offer light weight and excellent durability

–      New lightweight axles are lighter by 31 grams front and 32 grams rear 

Optional KX Accessories

–      KX DFI 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. An ECU setting is available, which 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 voltage

2015 Kawasaki KX450F Specifications*

Engine: Liquid-cooled, four-stroke single with DOHC and four-valve cylinder head
Displacement: 449cc
Bore x stroke: 96.0 x 62.1mm
Fuel Injection: DFI® with 43mm Keihin throttle body
Compression ratio: 12.8:1
Ignition: Digital DC-CDI
Transmission: Five-speed
Rake / trail: 27.9 degrees / 4.7”
Front suspension / wheel travel: Inverted Showa SFF-Air TAC fork with Triple Air Chamber, DLC coated sliders, 22-position compression and 20-position rebound damping adjustment / 12.4”
Rear suspension / wheel travel: UNI-TRAK® linkage system and Showa shock, 19-position
low-speed and 4 turns high-speed compression damping,
22-position rebound damping and fully adjustable spring
preload / 12.4”
Front tire: 80/100-21
Rear tire: 120/80-19
Front brake: Single rigid-mount 270mm Braking petal disc with dual-piston caliper
Rear brake: Single 240mm Braking petal disc with single-piston caliper
Overall length: 86.4”
Overall width: 32.3”
Overall height: 50.2”
Wheelbase: 58.8”
Ground clearance: 13.4”
Seat height: 37.8”
Curb weight: 247.1 lb
Fuel capacity: 1.64 gallons
Color: Lime Green
Wholesale distributor: Kawasaki Motors Corp., U.S.A.9950 Jeronimo RoadIrvine, California