2015 Kawasaki KX450F Race Test | Motocross Review

2015 Kawasaki KX450F Race Test

The 2015 Kawasaki KX450F needs no introduction. Monster Energy Kawasaki’s Ryan Villopoto has piloted the bike to the AMA Monster Energy Supercross championship each of the past four years. While that is undoubtedly an incredible feat and accomplishment, most riders are aware that Villopoto is racing a special, one-off machine constructed of countless factory parts and is supported by a team of technicians to constantly fine-tune the machine to his liking. Regardless, it is a recipe to win races and championships.

The saying, “What wins on Sunday, sells on Monday,” certainly applies to the 2105 Kawasaki KX450F. However, seeing a rider win so many races and championships means nothing if the production bike does not live up to its hype and perform on the track, as well. Thankfully, Kawasaki puts that research, development, and data acquired by Villopoto directly back into improving their production bike year after year. For 2015, this resulted in some small, but noticeable, changes. While Kawasaki released an all-around impressive motocross bike last year, the engineers went to work with the goal of improving the ergonomics, handling, and reliability for 2015.

Before divulging into how the KX performs on the track, it is important to explain the additional steps that must be taken before throwing a leg over the 2015 Kawasaki KX450F. Aside from topping the bike off with fuel and checking tire pressure, each air pressure chamber in the front forks needs to be checked before each and every ride. Last year’s Kayaba PSF forks have been replaced by Showa’s new SFF-Air Triple Air Chamber (TAC) fork, similar to the one that Ryan Villopoto used to win the AMA Supercross championship this year. The great thing about the new Showa TAC fork is that, with three separate air chambers, the rider can achieve the perfect setting for his weight, riding ability, and personal preference.

After my initial ride, it was apparent that the Showa SFF-Air TAC fork is undoubtedly an improvement over last year’s Kayaba PSF fork. The TAC fork is set up a bit softer than last year’s base setting, which is a good thing, as the front end bites well in corners and the does not want to push. The fork feels much more progressive as well. The progressive characteristics reduce headshake when negotiating the small chop, and have less bottoming resistance towards the bottom of the stroke.

For air pressure settings, I began with the stock, recommended pressure, which was 145 psi in the inner chamber, 7.25 psi in the outer chamber, and 131 psi in the balance chamber. After spinning plenty of laps at the Lucas Oil MX Park in Perris, Calif. with the stock setting, I went to the stiffer setting, as I was becoming more comfortable on the KX450F and gaining speed. The only chamber that called for an increase in air pressure for the stiffer setting was the balance chamber — the Kawasaki Genuine Air Fork Pump comes with the bike — which I increased to 145 psi. This proved to be the answer that I was looking for, as the fork was stiff enough to absorb the bigger landings, while still not wanting to push or wash out in corners.

A returning feature for 2015 on the forks is the diamond-like coating (DLC) treatment applied to the sliders, which reduces friction and heat and allows the performance of the fork to maintain consistency throughout the duration of a moto. No other production 450 comes standard with this treatment, and it a commodity among the factory bikes you see in the pits of an AMA Supercross or National Motocross race. On top of all that, the KX450F’s forks look very trick.

In the KX450F’s rear, the Showa shock received revised valving for firmer damping and a green shock spring. Due to my lighter weight, I opted for the softest settings. After making the necessary adjustments, the shock absorbed everything well including the small braking bumps, but was also progressive on bigger impacts. It worked perfectly in unison with the front end, so I was very pleased with how it performed. The shock receives a Kashima Coating treatment in order to reduce friction and heat. Similar to the DLC found on the front forks, the Kashima Coating reduces fading and helps maintain consistent performance as well.

The 2015 Kawasaki KX450F motor is in one word, fantastic. The only changes that Kawasaki made in the engine department for 2015 are a revised, bridged box piston for an increased compression ratio and better durability, and green engine plugs to match the Monster Energy Kawasaki factory race team.

Starting the fuel-injected KX450F is a snap. While it does require a deliberate, purposeful kick, the bike instantly fires to life regardless of whether hot or cold. The engine’s powerband provides everything that a rider looks for in a 450cc powerplant.

The KX450F’s power is perfectly placed, as it is smooth down low. This makes for excellent traction when exiting corners. It progressively rolls on into a meaty, mid-range that pulls strongly into the higher rpm’s. The top end power is aggressive and does not sign off until you decide to shut off the throttle. The motor makes power where you need it, but maintains the tractability necessary to keep you moving forward, and not spinning the rear tire.

Shifting through the five-speed transmission requires a deliberate, purposeful shift, especially when upshifting. However, it is by no means difficult or a struggle to grab the next gear. With that being said, I have not yet missed a shift on the 2015 Kawasaki KX450F. A little more effort put into shifting is well worth avoiding a false neutral.

Kawasaki’s pre-programmed plug-and-play ignition couplers return for 2015 with three different options: soft terrain (white), standard (green), and hard terrain (black). The soft terrain coupler provided a mellower bottom end hit, which helped when the track has deteriorated, becoming hard packed and rough. The standard coupler was my overall favorite as it balanced the tractable bottom end and the aggressive top end power. The black coupler worked best on the more loamy tracks, such as Cahuilla Creek Motocross (a track located in Anza, Calif.). However, once the track began to deteriorate and become rough, I opted to reinstall the stock coupler to tame the power.

Another feature returning for 2015 is Launch Control. Kawasaki was the first manufacturer to release this technology to the public on their production bike and it has proved to be an effective feature since its debut in 2012. Launch Control is activated by pressing and holding the button for three seconds. A red light on the button begins blinking, signifying that is has been activated. Launch Control is deactivated once the rider shifts into third gear. After some testing, Launch Control proved to be most effective in starting conditions that are slick, such as hard dirt or concrete. For softer dirt, I opted not to use Launch Control, as I wanted to put as much power the ground as possible.

The front brake received some attention for 2015, as Kawasaki opted to use an oversized Braking 270mm rotor, which replaced last year’s 250mm rotor. The new front brake is noticeably more powerful, while still maintaining a positive, consistent feel at the lever. The action initially feels a bit on the touchy side, but after spinning a few more laps and carrying more speed into corners, you adapt and are left with excellent braking power.

The 270mm rotor allowed me to carry more momentum into corners without any major concern for stopping before blowing through a rut or berm. After extensive testing, I was very happy with the 2015 Kawasaki KX450F’s front brake.

Possessing a range of adjustability is another great attribute of the Kawasaki KX450F. The bars can be moved either forward or backward, thank to two separate sets of bar-mount holes on the triple clamps. I opted to leave them in the rear position. However, the front mounting holes will suit a taller rider looking to get more room in the cockpit. The footpegs can be moved, as well, from either the stock position or dropped 5mm. Again, the 5mm lower position will work best for a taller rider who is once again, looking for more room to work with.

In the ergonomics department, the clutch on pull on the Kawasaki is consistent and predictable, and the clutch never faded. The levers have a neutral and comfortable feel. The standard Renthal 971 bend aluminum handlebars have an agreeable bend, and the grips are surprisingly soft for a stock application. The Bridgestone M403 front and M404 rear tires worked great, and maintained a sharp edge for several rides. The front and rear hooked up in every condition including soft, intermediate, and hard-packed dirt.

Routine maintenance on the KX450F is simple enough for anyone with general mechanical knowledge. Accessing, cleaning, and oiling the air filter consists of removing the seat and two tabs on the filter, which connect to the backfire screen to ensure a secure fit and seal. Changing the oil and oil filter is a snap as well. The KX engine and transmission oil are combined, so removing the drain bolt at the bottom of the engine is all that is necessary to drain all the oil. Changing the oil filter requires the removal of two bolts and the cover located directly in front of the clutch cover.

My only complaint is that Kawasaki has not addressed the loud, raspy-sounding stock muffler. At idle and low rpm, it is not a problem. However, when hitting the mid-range and top end of the power, it becomes ear piercing. This is not a big deal in the grand scheme of things as most riders invest in an aftermarket exhaust system.

With a powerful motor, a perfectly managed powerband, the Showa SFF-Air Triple Air Chamber front fork, and a stiffer rear shock, the 2015 Kawasaki KX450F is a bike that Intermediate and Pro level riders will love. Thankfully, Beginners and Novices can easily ride this bike, due to Kawasaki’s wide range of adjustability in the power, suspension and ergonomics department. The suspension features plenty of adjustability, and can be changed trackside for a plethora of different conditions, skill levels, and preferences.

If you are a rider/racer looking for a bike that suits everyone from a Novice to Pro that comes standard with race-ready equipment that can be tailored to fit, the 2015 Kawasaki KX450F meets all of those requirements.


Helmet: Vemar VRX9

Goggles: Oakley Airbrake MX

Neck Brace: Leatt-Brace GPX 5.5

Jersey, gloves, and pants: Moose Racing Sahara Racewear

Boots: Sidi Crossfire 2 SR

Andrew Oldar is sponsored by Moose Racing

Photography by Don Williams at MotoVentures

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: 27.9 degrees

Trail: 4.7 inches

Front suspension / wheel travel: Inverted Showa SFF-Air TAC fork with Triple Air Chamber, hard titanium-coated sliders, 22-position compression and 20-position rebound damping adjustment / 12.4 inches

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 inches

Front tire: Bridgestone 80/100-21

Rear tire: Bridgestone 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 inches

Overall width: 32.3 inches

Overall height: 50.2 inches

Wheelbase: 58.8 inches

Ground clearance: 13.4 inches

Seat height: 37.8 inches

Curb weight: 247 pounds

Fuel capacity: 1.64 gallons

Color: Lime Green

2015 Kawasaki KX450F MSRP: $8699