To maintain its edge in this fiercely competitive class, the 2019 KX450 benefits from a new engine mounted in its leanest chassis to date, enabling it to turn even quicker lap times, and make it the most powerful machine in the paddock. Complementing its already high performance, a number of new features – including finger-follower valve actuation, electric start and a hydraulic clutch, which are all firsts for a Kawasaki motocrosser – further elevate its race-winning potential.
Designed with mid-level to expert riders in mind, the KX450 motorcycle has always been built with one goal in mind: to put riders on the top step of the podium. And for over 40 years KX brand motocrossers have been extremely successful at doing just that.
The new engine boasts an increase in peak power of approximately 2.5 kW (3.4 PS), while a flatter torque curve makes it easier to get on the gas. Finger-follower valve actuation (a valve train designed by Kawasaki’s MotoGP & World Superbike engineers) enables larger diameter valves and more aggressive cams. Downdraft style intake and reduced friction loss (care of new plain bearings for the connecting rod big-end) further contribute to the power gains. Being able to restart an engine quickly after a spill can mean the difference between keeping your lead, or having to fight your way back through the pack. Kawasaki’s first electric start on a motocrosser makes restarting the engine as easy as pushing a button. The electric starter is powered by a lightweight lithium ion battery
Kawasaki’s first hydraulic clutch on a motocrosser offers more direct feel and lighter lever action. Less play as the clutch heats up during heavy use results in more consistent feeling.
Complementing the powerful engine, light, nimble handling contributes to the KX450’s quick lap times. While the addition of electric start and the return to a coil-spring fork add weight, efforts were made to keep the weight gain to a minimum. The result is the KX450’s leanest chassis to date, and a highly-competitive, low overall weight of only 110.0 kg – a gain of only 1.3 kg.
Matching the KX450’s increased power, increased front and rear traction ensure the bike can put power to the ground and get around corners quickly. A larger diameter front axle (a hint from our racing teams) helps at the front, while revised rear suspension layout and new linkage ratios benefit the rear.
Being able to restart an engine quickly during a race can mean the difference between keeping your lead, or having to fight your way back through the pack. Kawasaki’s first electric start on a motocrosser makes restarting the engine as easy as pushing a button. Starting is electric only, via a button located on the right grip.
High-performance piston, featuring the same design used on our factory racers, contributes to strong performance at all rpm. A short skirt, reinforced external ribs and the use of a bridged-box bottom, featuring internal bracing, contributes to a light, strong piston design. Revised design and strength optimisation results in an even lighter piston (259.8 g >> 243 g), further reducing reciprocating weight and contributing to the engine’s increased performance. A change from needle bearings to plain bearings for the connecting rod big-end reduces mechanical loss, contributing to overall performance. Thinner air cleaner element restricts airflow less, contributing to increased performance at all rpm.
The New Uni-Trak rear suspension system mounts the suspension arm below the swingarm, allowing a longer rear suspension stroke. The longer stroke in turn allows more precise rear suspension tuning. Revised linkage ratios contribute to increased rear wheel traction. Shifting the shock 5 mm to the right allows room for the new downdraft style engine intake. Revised rear shock layout also contributes to increased rear wheel traction. The rear shock features dual compression adjustability, allowing highspeed and low-speed damping to be tuned separately. A self-lubricating alumite coating on the tank cylinder helps prevent wear abrasion, and reduces friction for smoother suspension action.
A choice of four handlebar positions and two footpeg positions allows riders to tailor their riding position to suit body size and preference. Upper triple clamp with two sets of handle mount slots and reversible handle mounts offers riders a choice of four handle positions to choose from: 25 mm forward, 15 mm forward, STD and 10 mm back.
Even for top-level riders, controlling the massive power of a 450cc-class motocrosser off the start requires a high degree of throttle control and clutch finesse. By slightly reducing this power, Launch Control Mode helps riders maximise traction, increasing the chance of getting a good start. Launch Control Mode works in 1st and 2nd gear (and Neutral). Once the rider shifts into 3rd gear, the system is automatically disengaged, switching back to the normal engine map. System designed to the same specifications as that of our AMA factory racers.
Adjusting engine settings to suit conditions has never been easier than with the KX’s DFI couplers. Plug-and-play style system is quick, easy and stress-free.Instead of a single engine map, the ECU features three (four, counting the Launch Control Mode map). Initial settings for the three maps are: Standard, Hard (conditions) and Soft (conditions). Using provided DFI couplers, riders are able to easily switch between the three maps to suit riding conditions. (Plug is conveniently located on the right side of the head pipe for easy access without having to remove any parts.) Maps can now be changed while the engine is running. ECU settings include programming that enhances traction by retarding ignition when the rear wheel speed increases too quickly (i.e. from sudden, excess wheel spin).