2015 Kawasaki KX450F: FIRST LOOK

Cycle News Staff | July 1, 2014
  2015 Kawasaki KX450F

The 2015 Kawasaki KX450F features new forks and updated rear suspension.

For 2015 the Kawasaki KX450F takes on big changes in the suspension department, including smaller refinements all around. But the big news is the 450’s new fork. It has been upgraded to Showa’s latest SFF-Air TAC Fork with Triple Air Chamber.

Here’s what Kawasaki has to say about its new 2015 KX450F:

  2015 Kawasaki KX450F

The new KX450F is fitted with an oversized Braking front brake.

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.


  All-new Showa air forks for the 2015 KX450F

The KX450F gets the latest SFF Triple Air Chamber (TAC) Fork from Showa.

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 new Showa forks are recognizable by the lower reservoir.

You can recognize the new Showa fork with its lower reservoir.

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.

A digital air pump comes with every purchase.

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.

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