KX450 (MY21) – Kawasaki

With more Supercross and Motocross championships than any other manufacturer, the KX name is synonymous with winning. The KX450 motorcycle represents the flagship of the KX lineup, built with the sole purpose of dominating the track. Over the past four decades, we’ve learned what it takes to win and stay on top. Our dedication to building the ultimate machine is undeniable, and the KX450 represents this to the fullest.

ENGINE

KX450 features a valve train designed by Kawasaki’s World Superbike engineers. Finger-follower valve actuation enables the use of large-diameter valves and aggressive cam profiles. A short skirt, reinforced external ribs and the use of a bridged-box bottom, featuring internal bracing, contributes to a light, strong piston design. A light piston (243 g) reduces the reciprocating weight and contributes to the engine’s performance. A change from needle bearings to plain bearings to the connecting rod big-end reduces mechanical loss = better engine performance.

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 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.

SUSPENSION AND BRAKES

The 49mm Showa Coil Spring Front Fork combined with A-KIT Technology deliver excellent handling. Large-diameter inner tubes allow the use of large damping pistons for race-winning performance while a large-diameter front axle provides exceptional front-wheel traction. Kashima Coat creates a hard, low-friction surface on the outer tubes. The hard coating helps prevent wear abrasion on the inside of the tubes, ensuring the sliding surfaces remain smooth for a long time, while the outside is protected against corrosion. The lubricating material in the coating contributes to smoother suspension action.

The Uni-Trak rear suspension system features adjustable dual-range (high- and low-speed) compression damping, adjustable rebound damping, and adjustable preload. The result is optimal damping and rear-wheel traction. Swingarm rigidity matched to the frame, contributes to increased rear traction. Chassis balance and settings were all set to suit race-experienced riders. The centre of gravity and key dimensions (swingarm pivot, output sprocket and rear axle locations) are chosen so that the rear tyre drives the bike forward (instead of causing it to squat).

Petal disc brakes are among the KX450’s numerous factory-style components. The stylish discs contribute to both sporty looks and a high-quality appearance. Oversized semi-floating 270 mm diameter front disc contributes to strong front brake force, as well as superb controllability. The front brake master cylinder offers better initial control, while contributing to overall braking performance. A large-diameter rear disc 250 mm diameter matches the large front disc and contributes to stronger stopping power.

FRAME

The upper triple clamp with two set of handle mounts offer riders a choice of four handlebar positions, from: 25 mm forward, 15 mm forward, STD and 10 mm back. Two footpeg positions allows riders to tailor their riding position to suit body size and preference. Slim shrouds are positioned close to the frame. Being slim where they come in contact with the rider’s legs, the single piece shrouds are easier to hold on to. The frame widens at the ankles to offer the rider better grip and narrows near the bend below the seat to allow a slim riding position. Smooth engine covers are also designed to not impede rider movement.

Based on feedback from our factory race teams, the KX450 features a large-diameter front axle shaft 22 mm diameter, which contributes to greater front-end traction. Dunlop MX3S tyres contribute to increased front and rear traction. Top of the fuel tank is designed to allow a flat progression from the seat to the tank, which gives the rider greater freedom of movement when changing riding position. The top surface is slip-resistance for seated grip.