2021 KX450X


KX450X Right Facing


When it comes to KX motorcycles, winning runs in the family. The all-new cross-country KX450X motorcycle is powered by technology that hails from a legacy of champions and tuned to take on the toughest terrain. Get the off-road edge on the bike built to ride ahead of the rest.

Based on the championship-winning KX450 motocrosser, the new cross-country racer boasts an arsenal of factory-style features. Cross-Country specific tuning for the engine, suspension and brakes, complemented by a 21”/18” wheel combination fitted with enduro-type tyres, and convenient standard features like a side stand and skid plate make the new KX450X even more attractive for cross-country competitors.






KX450X left Facing


The same championship-proven engine performance found in KX motocross bikes is what propels the all-new cross-country KX450X motorcycle. This fuel-injected 449cc 4-stroke engine delivers the type of hard-hitting power and a flat torque curve that encourages quick acceleration.

  • Engine maps are optimized for cross-country racing, delivering the ideal amount of useable power.
  • Electric start makes starting the engine as easy as a push of a button.
  • A coned disc-spring hydraulic clutch offers a direct feel, light lever action, and consistent performance.

2021 KX450XC start button

Electric Start

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 on the right grip. 

2021 KX450XC clutch spring

Hydraulic Clutch

The hydraulic clutch offers direct feel and light lever action. Less play as the clutch heats up during heavy use results in more consistent feeling. The use of coned-disc springs lightens the clutch actuation when the lever has been pulled in, and a wider clutch engagement range for rider control.

2021 KX450XC 18" rear wheel

Wheel & Tyres

With a 21" front and 18" rear wheels encased in Dunlop Geomax AT81 enduro-type tyres, these are well-suited to situations encountered in Cross-Country riding ensuring that you get the KX450X's power to the ground.


2021 KX450XC skid plate


KX factory-style skid plate to protect the underside of the engine and and facilitate sliding over obstacles.

Convenient side stand comes in handy when stopping away from the paddock area.

KX450X forks

Front Suspension

High-performance ø49 mm inverted coil-spring fork. Super-hard titanium coating on the outer surface of the fork inner tubes helps prevent wear abrasion. Kashima Coat creates a hard, low-friction surface on the outer tubes.

KX450X left

Rear Suspension

The New Uni Trak rear suspension system mounts the suspension arm below the swingarm, allowing a longer rear suspension stroke. The rear shock features dual compression adjustability, allowing high speed
and low-speed damping to be tuned.

2021 KX450XC front brake


KX450X brake package optimised for Cross-Country riding delivers strong stopping power and a high level of control.

  • ø240 mm rear petal disc
  • ø270 mm front petal disc
2021 KX450XC fat bars

Fat Bars

Factory-style ø28.6 mm (1-1/8”) Renthal aluminium Fatbar, a popular after market part, is standard equipment. The thick handlebar helps reduce vibration and shocks transmitted to the rider.

Engine Design

KX450X 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.

2021 KX450Xc piston

High Performance Piston

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 enhances the engine’s performance. Needle bearings to the connecting rod big-end reduces mechanical loss = better engine performance.

KX450X smooth transition

Aluminium Frame

Light and nimble handling is achieved thanks to the use of the lean, lightweight chassis of the legendary KX450 motocross bike. A well-balanced, slim aluminum perimeter frame helps keep the overall weight down and allows for light handling and slim ergonomics.

2021 KX450XC frame


Slim aluminium perimeter frame is a lightweight construction composed of forged, extruded and cast parts. Overall rigidity balance was optimised to deliver both light handling and excellent traction. Engine is used as a stressed member, contributing to the frame’s rigidity balance.

Engine Tuning

Adjusting engine settings to suit conditions is simple with the three DFI couplers. Plug-and-play style system is quick, easy and stress-free. Each of the three maps can be reprogrammed using the optional KX FI Calibration Kit.

  1. MX Hard conditions (default)
  2. MX Standard conditions
  3. MX Soft conditions.
2021 KX450XC launch control

Launch Control

The press of a button, riders can activate a separate engine map designed to ensure efficient starts in low-traction conditions. The Launch Control Mode map retards ignition timing, allowing tyres to gain grip, and allowing riders to
focus on their lines.

KX FI Calibration Controller (Accessory)

 KX FI Calibration Controller enables riders to make changes to engine maps by plugging into the ECU without a PC or battery. Comes equipped with seven preset map settings, a built in colour LCD screen, transfer and diagnostic cable SD card, user manual and carry case.


Lightweight and compact the proven Li-ion Battery helps keep the weight minimal.

2021 KX450XC footpeg

Adjustable Footpegs

The two position footpeg brackets enables riders to vary the footpeg position to find the right fit. The footpeg bracket can be lowered 5mm from the standard position. Lightweight, wide-style footpeg design for excellent grip and superb control.


Adjustable Handle Mount

Upper triple clamp with two sets of handle mount slots and reversible handle mounts offers riders a choice of four handle positions: 25 mm forward, 15 mm forward, STD and 10 mm back.


2021 KX450XC flat seat

Flat Lines

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.

KX450X smooth transition

Smooth Surfaces

Bodywork on the KX450X features long, smooth surfaces that make it easy to slide. Seams between the shrouds, seat and side covers are flush for moving around on the bike. In-mould graphics on the shrouds are ultra-smooth and ensure the race-style graphics are not easily damaged.

2021 KX450X

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KX450X  (KX450KMFNN)

Engine Type4-stroke, liquid cooled, single cylinder
Displacement449 cm³
Bore x Stroke96.0 x 62.1 mm
Compression Ratio12.5:1
Valve SystemDOHC, 4 valves 
Fuel SystemFuel injection: ø44 mm x 1
IgnitionDigital DC-CDI
StartingElectric starting
Transmission5-speed, return
ClutchWet multi-disc, manual
FramePerimeter, aluminium
Wheel travel - front305 mm
Wheel travel - rear307 mm
Tyre Size-front80/100-21 (51M)
Tyre Size-rear120/90-18 (65M)
Suspension - front49 mm inverted telescopic spring fork with adjustable compression and rebound damping
Suspension - rearNew Uni-Trak with adjustable dual-range (high/low-speed) compression damping, adjustable rebound damping and adjustable preload
Brakes - frontSingle 270 mm semi-floating petal disc with dual piston caliper
Brakes - rearSingle 240 mm petal disc with single piston caliper
L x W x H2,185 x 820 x 1,265 mm
Wheelbase1,485 mm
Ground Clearance335 mm
Seat height950 mm
Fuel capacity6.2 litres
Curb Mass111.6 kg (includes full fuel tank, all fluids at optimum levels)
ColourLime Green - 2021 model may show "XC" on the shroud graphic.
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