Kawasaki just revealed its 2018 motocross line and there are some surprises. The KX250F was completely redesigned last year, so we didn’t expect much change so soon. But apparently, Kawasaki had more on its agenda. Here’s the official press release:
Kawasaki’s powerful race-winning motocross bike is equipped with a potent, lightweight engine package that is derived from its factory race team efforts. The 4-stroke, single cylinder, DOHC, water-cooled 449cc engine has been designed for instantaneous response at the crack of the throttle and continues through to its strong top-end pull for peak performance.
The cylinder is offset 8.5mm forward to reduce mechanical loss through friction from the piston movement, thus enabling more efficient power generation. A special coating used on the intake port cores during the casting process make ports ultra-smooth, which increases efficiency and performance at all RPM.
36mm titanium intake valves, similar to those found in Kawasaki Ninja® sportbikes, have a slim throat angle and reduced recess to increase high-RPM performance. Intake cam settings maximize low-RPM performance, while a lightweight camshaft aids in throttle response and extends over-rev. A bridged-box piston design, which features a 12:8:1 compression ratio, is similar to those seen on the Monster Energy® Kawasaki race team’s factory race bikes and matches the intake valve shape. The piston has optimum rigidity for maximum high-RPM power and durability.
A resonator chamber has been fitted to the exhaust system header, which assists in low-RPM power and helps to reduce the decibel sound level. The sleek air box design has eliminated the use of any steel parts, resulting in weight savings. Intakes and air box shape underneath the seat help ensure clean-consistent airflow, maximizing engine response and reducing intake noise.
In the transmission, lightweight gears and shafts reduce weight and retain their overall strength while contributing to the motorcycle’s winning performance. The engine cases, which feature a scavenger pump on the right case, have been constructed of the lightest materials and are designed to meet the highest standards of durability.
Contributing to the race-winning engine characteristics, the digital fuel injection system of the KX450F features a coupler package that has set the industry standard. Each KX450F motorcycle comes standard with three different couplers, easily allowing riders to change fuel injection and ignition mapping to suit their riding style or track conditions. The four-pin DFI® couplers are designed for standard, hard or soft terrain settings. Changing the coupler is as simple as connecting the coupler cap of choice. For riders looking to fine tune their ECU the KX FI Calibration Kit (Handheld) is offered as part of a selection of Kawasaki Genuine Accessories, which allows access to the fully programmable ECU. The handheld device eliminates the need for a trackside laptop and gives riders the ability to create custom maps for precise adjustment of fuel and ignition settings. The user-friendly device can store up to seven preset maps and is PC-compatible.
The launch control system of the KX450F motorcycle is a favorite for riders of all skill levels who are focused on getting to the first turn ahead of their competition. The push-button activation retards ignition timing in first and second gear, helping maximize traction and put the bike’s potent power to the ground. Once the rider shifts into third gear, normal ignition mapping immediately resumes and full power is restored.
Kawasaki’s engineers have sacrificed countless hours working alongside the factory racing team to develop the ultimate aluminum perimeter frame that is aimed towards providing precise cornering through front-end feel and maximum agility at high speeds. The perimeter spars have been designed to ultra-thin specifications for a narrow profile and comfortable feel. A lightweight, rigid swingarm is used to help rear-wheel traction and overall rider feel and handling performance. The alloy swingarm is constructed of a cast front section and twin tapered hydro-formed spars in a raw aluminum finish. Forged chain adjusters are also equipped with a self-locking rear axle nut. The axle nut holds 80lb-ft torque without the need of a cotter pin, simplifying maintenance at the track.
The upper and lower triple clamps are inspired by the factory race team bikes, and enable quick turn-in through the optimal rigidity and front-end feel, ultimately making the motorcycle a rider’s dream when cornering.
SUSPENSION & BRAKES
For 2018, the KX450F motorcycle once again features industry-leading technology from the Showa SFF-AIR TAC (Separate Function Fork, Triple Air Chamber), which separates the damping and shock absorption duties into the individual fork legs. The left fork contains the damping assembly and the right fork contains the air spring. Instead of the steel coil springs found in conventional forks, the SFF-AIR TAC’s right fork tube has three chambers filled with pressurized air that act as a “spring.” With the elimination of steel coil springs, friction is reduced, and provides an extremely smooth action throughout the fork’s stroke. This has the added benefit of weight reduction and allows a larger damper piston to be used, further smoothing the action. It is lightweight and rigid, contributing to superior riding performance and front-end feel. The low friction design, including a DLC coating to the outside of the lower fork tubes also contributes to the extremely smooth fork action. Incredibly precise settings can be adjusted by simply changing the air pressure and using the 22-position compression and 20-position rebound damping adjustments. Changing air pressure covers a range of settings offered by optional springs in a standard fork, including quick changes of ride height, without needing to disassemble the fork tubes.
On the rear suspension, Kawasaki’s Uni-Trak® linkage system is designed to work in conjunction with the aluminum frame and swingarm. The linkage, which is mounted below the swingarm, allows for a longer rear suspension stroke and maintains a low seat height. Dual compression adjustability from the Showa shock allows high-speed and low-speed damping rates to be set separately. The shock reservoir has a friction-reducing internal Kashima coating for improved suspension action. The race-oriented rear suspension offers class-leading action and adjustability on par with the Showa SFF-AIR TAC fork. The fully adjustable shock allows for precise settings to help keep the rear wheel planted and the rider out front.
Kawasaki offers an optional rear suspension linkage tie rod for riders who are seeking an edge over their competition. It is 1mm longer than stock and can be used to reduce seat height by 4mm to give the rider adjustment options.
An oversized 270mm, petal-shaped front brake rotor from the renowned manufacturer, Braking®, is fitted to keep up with its powerful engine and help riders turn quicker lap times than the competition. Its purpose is to provide powerful stopping, good lever feel, and consistency in all conditions. The rear is equipped with a 240mm petal-shaped Braking® rotor.
Kawasaki continues its unmatched commitment towards success and provides riders with class-leading comfort thanks to its adjustable handlebar mounting system and footpegs to fit a variety of riders and riding styles. The handlebars feature 4-way adjustable mounts. The multi-position handlebars offer two mounting holes with 35mm of adjustability, and the 180-degree offset clamps boast four individual settings to suit different size riders. The wide 50mm footpegs feature dual-position mounting points, with a lower position that reduces the standard setting by an additional 5mm. The lower position effectively lowers the center of gravity when standing, and reduces knee angle when taller riders are seated.
The 2018 Kawasaki KX450F motorcycle can be made to suit a large range of riders thanks to its flat seat design, adjustable handlebar and footpegs and adjustable suspension components. This perfectly complements the wide range of damping settings as well as the DFI® couplers and optional handheld KX FI Calibration Kit, allowing the rider to find the ideal engine characteristics to suit a particular track or conditions. While the base settings on the KX450F motorcycle are based on extensive testing, including racing, the motorcycle provides a huge range of technology and adjustment to help ensure every rider can experience the incredible ability of this extremely capable motocross bike.
BODYWORK & SEAT
To go along with its race proven performance, the 2018 KX450F motorcycle features aggressive styling along with in-mold graphics on the radiator shrouds that retain the racy look necessary when finishing at the top of its class. The bodywork has been sculpted to match the narrow chassis design; the fuel tank has been designed to lower the overall center of gravity, increasing maneuverability. With performance in mind, the flat design easily allows for movement when changing riding position, while also allowing the rider to sit further forward.
Complementing the bike’s eye-catching appearance are the green engine plugs, oil cap, and generator cover plugs, as well as green alumite suspension adjusters and black alumite wheels. The clutch cover features embossing that is designed to appear over time.
A large synthetic skidplate offers a level of protection for the bottom of the 2018 KX450F motorcycle’s class-leading engine, with minimal weight, and features oval holes in order to facilitate mud removal.
Color: Lime Green
2018 KAWASAKI KX250F
The dominating Kawasaki KX™250F motorcycle returns for 2018 with a list of enhancements to keep the KX250Fon top as the single-most dominant motocross bike of the last decade. The 2018 model offers an updated engine for an improved torque feeling throughout the rpm range, as well as improved holeshot performance. The KX250F still features a lightweight, slim and rigid chassis, but now features revised suspension to deliver improved bump absorption and suspension action. These improvements all mean one thing: faster lap times—the 2018 Kawasaki KX250F was found to have significantly faster lap times on the Kawasaki test track compared to the 2017 model.
The 2018 Kawasaki KX250F:
- Improved power and torque throughout the rev range
- Improved suspension settings for better compliance, resulting in quicker lap times
This year’s KX250F is built with race-winning components to help Kawasaki riders get to the top step of the podium. From the showroom to the racetrack, the performance of Kawasaki’s KX™ family of motorcycles is proof of its engineering pedigree. It truly is the Bike that Builds Champions.
- New throttle body and fuel injector angle, for increased
torque feeling throughout rpm range
- New fuel pump with increased output pressure
- New intake boot
- New intake camshaft
- New cylinder head with revised intake tract and compression ratio (13.4:1)
- New exhaust header with longer and larger piping
Highly acclaimed for its high output and smooth power delivery, the KX250F motorcycle is back with new tuning and improved performance. Tuned to best suit race-experienced riders, the 249cc liquid-cooled, 4-stroke single’s wide power-band focuses on high-rpm performance that extends way into the over-rev. Riders will feel more power from low to high rpm, and experience improved over-rev characteristics.
Entering its second year after a major redesign, Kawasaki engineers concentrated on fine-tuning the 2018 KX250F’s performance in multiple ways. The intake path has been revised with a shorter intake funnel and redesigned duct. Intake valve timing has also been advanced. The KX250F features a new fuel pump with increased output as well as a new injector placement angle, bringing more precision and improved performance. The Fuel Injection system and ECU also now have revised settings, providing performance the rider can feel at the flick of the throttle. The exhaust header is now larger and longer, further increasing torque and power output, while retaining the resonator chamber.
These changes have improved the power feeling from ultra-low to high rpm—the engine feels stronger at all rpm. The 2018 KX250F motorcycle also features improved over-rev characteristics, resulting in less rpm drop when shifting, keeping the bike in the sweet spot of power while trying to cut the fastest lap possible. While power and torque have improved, the KX250F is also now easier to use in high-rpm operation.
The dual-injector fuel injection system of the KX250F is a key component to its performance; the 2012 KX250F was the world’s first production motocross bike to use such a system. Unlike a standard fuel injection system, which uses one injector downstream of the throttle valve, the system on the KX250F motorcycle uses a second, upstream injector located close to the airbox. The downstream injector is used to help ensure smooth, instant response featuring a finer atomization with more holes in the injector itself. The downstream injector creates that stronger low-to-mid range power and quick throttle response, while the upstream injector is charged with providing top-end power.
As rpm and throttle position increase, primary operation switches from the downstream injector to the upstream injector, depending on whether in a low (1st, 2nd) or high (3rd, 4th, 5th) gear, the transition is gradual and seamless. The upstream injector’s greater distance from the combustion chamber gives the fuel particles and intake air more time to mix, as well as allowing the mixture to cool before entering the combustion chamber, both of which contribute to more efficient filling, and ultimately more power.
- Lightweight ECU, with revised settings
- DFI® Connectors activate three separate engine tuning maps (standard, hard, soft)
- Optional KX FI Calibration Kit (Handheld) requires no tools, laptop or battery
The lightweight ECU of the KX250F motorcycle was designed specifically to withstand the rigors of motocross racing, while still providing a wide variety of tuning options. The Kawasaki KX250F provides three engine maps that come pre-loaded into the motorcycle’s ECU that are easily accessible through the DFI® coupling plug. These three color-coded couplers are designed to tune for hard, medium or soft track surfaces, and allow riders to find the ideal power delivery for a particular terrain.
Using the optional KX FI Calibration Kit (handheld), sold separately as a Kawasaki Genuine Accessory, a rider can store and select from up to seven separate engine maps. The kit includes a portable handheld calibration tool, which enables riders to make changes to the engine maps without the need of a PC, laptop or battery, making it easy to tune at the track. The handheld calibration module plugs in thanks to an additional harness not included in the kit.
FRAME & SUSPENSION
- Lightweight, aluminum perimeter frame design
- Showa 48mm Separate Function Front Fork (SFF Type 2)
Unchanged since the introduction of a new frame in 2017, the slim chassis design contributes to light, nimble handling. The flat seat makes it easy for riders to shift their weight, offering a high level of riding freedom. New for 2018 are fine-tuned front and rear suspension settings that deliver improved bump absorption, which result in improved handling. Kawasaki test riders found improved times in tight and open sections of the Kawasaki test track.
Up front you’ll find revised Showa 48mm Separate Function Front Forks (SFF Type 2) with works-style internal construction that locates its damping assembly in the left fork tube and a spring in the right. The Separate Function Front Fork construction contributes to a planted feel at the front, superb damping performance and ride comfort with greater bottoming resistance. It also has excellent agility when on the brakes or when landing jumps. For 2018, revised settings contribute to greater precision over braking bumps and through corners.
The Uni-Trak® rear suspension with Showa shock features revised settings, new for 2018. These changes contribute to improved ride feel, traction, and increased rear-end feedback. The rear shock linkage mounts are below the swingarm to maximize wheel travel and cornering stability. Dual compression with high and low speed adjustability offers a wide range of tuning options. Self-lubricating Kashima coating on the inner shock body improves wear resistance and shock action.
The KX Launch Control system is a major advantage in getting out of the starting gate straight and fast. Launch Control Mode has the greatest effect within the first few seconds of releasing the clutch off the start.
The KX250F features a Launch Control system that, with the simple press of a button, allows riders to activate a separate engine map designed to assist starting in certain conditions. The Launch Control Mode map retards ignition timing, allowing tires to gain grip in low-traction situations, and allows riders to focus on their lines. Launch Control remains active through first and second gear, until the rider shifts into third gear, and then it returns to normal engine timing.
Even for top-level riders, controlling the hard-hitting power of a KX250F motocrosser off the start requires a high degree of throttle control and clutch finesse. By optimizing this power, Launch Control Mode helps riders maximize traction, increasing the chance of getting a good start.
Contributing to the racing components found throughout the KX250F are the brakes. Up front is an oversized 270mm Braking®brand rotor, which delivers strong braking force and superb control. The petal style discs contribute to both sporty looks and help deflect debris. Rear caliper guard helps protect the caliper from damage.
Color: Lime Green