2021 Kawasaki KX450X Guide

2021 Kawasaki KX450X

2021 Kawasaki KX450X 2021 Kawasaki KX450X 2021 Kawasaki KX450X 2021 Kawasaki KX450X


Introducing the new 2021 Kawasaki KX450X…

The all-new 2021 KX450X has been designed as the flagship model of the off-road competition KX lineup. Whether in the woods, desert, or cross-country the KX450X is a race-ready championship winning machine right off the showroom floor, and shares numerous winning traits of its motocross counterpart, the KX450.

An cross-country race machine tuned for more experienced riders, the 449cc liquid-cooled, four-stroke engine, slim aluminum perimeter frame, Showa A-KIT technology suspension, hydraulic clutch and electric start are the ultimate combination of a championship winning package.
The KX450X 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.

With a rich history in off-road racing, Kawasaki adds the new KX™450X to its off-road line-up. The new crosscountry racer retains all of the championship-winning performance and factory-style features of the KX™450 motocross racer but adds X-specific engine tuning and suspension settings, 21/18-inch wheels fitted with enduro-type tires, and convenient standard features like a side stand and skid plate.



2021 Kawasaki KX450X Totalmotorcycle.com Key Features
  • ALL-NEW Off-road optimized engine and suspension settings
  • ALL-NEW 21” front wheel and 18” rear wheel
  • ALL-NEW Dunlop GEOMAX AT81 tires
  • ALL-NEW Brake components
  • ALL-NEW Skid plate
  • ALL-NEW Kickstand


The nature of off-road racing differs from that of motocross/supercross. Therefore the KX™450X has the following changes from the base KX™450.

  • While all of the power of the KX450 motocross racer’s engine is retained, fuel injection/ignition mapping was optimized to provide the ideal amount of useable power for cross country racing situations. Riders can further tailor the power delivery to their specific needs using the Kawasaki Genuine Parts & Accessories KX FI Calibration Kit.
  • One-tooth larger rear sprocket than the KX450 motocross racer provides shorter gearing more suitable to navigating off-road courses with loose rock sections, slick uphills, root-infested trails, and other obstacles requiring lower gearing.
  • High-performance 49mm inverted coil-spring fork and New Uni Trak rear suspension come directly from the KX450 motocross racer. But since cross country courses don’t have the big jumps of a motocross track, spring rates and damping settings are optimized for off-road racing to offer increased feedback, especially when riding on aggressive trails.
  • X-specific front brake pads optimize off-road brake performance.
  • Off-road specific 18-inch rear wheel allows tire to have a larger sidewall for a smoother ride over rocks and roots, plus better resistance to pinch flats when riding in such terrain. Dunlop AT81 tires are designed to provide maximum traction in the cross country riding environment.
  • Standard side stand provides convenient parking out on the trail.
  • Skid plate and enhanced engine guards help protect the engine from trail debris.


The championship-proven technology of KX™ race machines has now been purposely tuned for off-road competition. Kawasaki is proud to announce all-new off-road competition KX™ models with the all-new 2021 KX™250X and KX™450X models.

As a brand that has a rich history in off-road racing with more than 25 championships in WORCS, National Hare & Hound, GNCC, and Endurocross over the past 20 years, there’s no denying the all-new off-road KX models are powered by technology that hails from a legacy of champions.

The KX250X and KX450X share many winning traits with their motocross counterparts including the engine, frame, chassis, and styling, paired with unique cross-country tuning and settings such as suspension settings, gearing, off-road 21”/18” wheel combination, Dunlop Geomax AT81 tires, brake components, skid plate, and kickstand. The softer suspension settings and shorter gearing ratio help to create the optimal handling package for the race ready off-road KX lineup.

Developed to dominate off-road racecourses in both the woods and the desert, the cross-country KX lineup offers riders an arsenal of factory-style features along with the dominant engine and chassis performance right off the showroom floor.




2021 Kawasaki KX450X Totalmotorcycle.com Features and Benefits

The engine has potent peak power while a flat torque curve makes it easy to accelerate and find traction. Kawasaki’s multi-time World Superbike Championship-winning engineers designed the finger-follower valve train that, combined with minimal friction loss and steep downdraft style intake tract, contributes to the power.

4-Stroke Engine

  • Light piston helps minimize reciprocating weight and contribute to engine performance. The piston features a similar bridged-box bottom design featuring fully flush internal bracing as those used on the factory racers, with a short skirt and reinforced external ribs resulting in a lighter, stronger piston.
  • The piston skirt is coated with a dry film lubricant to reduce friction between the piston and cylinder for increased performance.
  • Plain bearings at the connecting rod big end reduce mechanical loss and help boost power.
  • Cylinder offset is 8.5mm forward to reduce friction and enable more efficient power generation.
  • Wedge-shaped crank web increases offsetting moment for a balance factor close to 60 percent, which is close to the factory bike. The high balance factor contributes to reduced engine vibration, smoother power delivery and increased performance, especially at low rpm where response is noticeably snappier.
  • Aluminum cylinder with chrome composite plating(KP) provides rapid heat transfer, superb wear resistance and optimum lubrication retention for increased performance and durability.
  • Semi-dry sump(KP) lubrication system for quicker engine response. The majority of oil is stored in the transmission to keep excess oil away from the crankshaft and prevent power-robbing stirring loss. A shallow chamber collects oil at the bottom of the crankcase, where a scavenge pump moves it to the transmission. This allows the crank to be located as low as possible to help lower the center of gravity.


Race-tuned 4-Valve Cylinder Head(KP)

  • Finger-follower valve train designed by Kawasaki’s multi-time World Superbike Championship winning engineers allows large diameter valves, aggressive cam profiles and high rev limit for high-rpm performance.
  • Finger-follower valve actuation reduces valve train mass by approximately 6.5 percent compared to tappet-style actuation, as well as reducing friction at the cam lobe. DLC (Diamond-Like Carbon) coating on the followers help prevent wear.
  • Aggressive camshaft lobes have a chromium nitride coating for durability.
  • 40mm intake and 33mm exhaust valves are titanium to help reduce weight.
  • Chromium steel valve spring retainers are also light and provide reliable valve control at high rpm.
  • When the cylinder head is cast the intake port cores are coated so that they have extremely smooth surfaces for increased intake efficiency.


Downdraft Intake

  • Downdraft-style intake routing has a 20˚ approach angle for a straight approach for intake air that enhances cylinder filling efficiency and contributes to power.
  • 44mm throttle flows abundant air for maximum performance, especially at high rpm and overrun. A reversed orientation tilts the butterfly valve open from the top for optimum fuel atomization from the top-mounted injector.
  • Fine atomizing, 12-hole injector sprays 75 micron droplets and contributes to smooth power delivery and superb engine response at partial throttle.


Resonator Exhaust

  • Long header pipe contributes to robust low-end power.
  • Exhaust system features a resonator chamber to effectively increase exhaust pipe length and reduce exhaust noise.


Coned Disc-spring Hydraulic Clutch

  • The clutch uses a single coned disc spring instead of five coiled springs for light clutch actuation when the lever is pulled and a wide clutch engagement range that helps the rider control the clutch. The coned disc spring rate decreases as the clutch lever is pulled in so that lever action is very light to help reduce rider fatigue during long off-road events.
  • Kawasaki’s hydraulic clutch offers direct feel and light lever action. Less play as the clutch heats up during heavy use results in a more consistent feel.


Electric Start

Provides the convenience of quick and easy push-button engine starting.

  • Powered by a lightweight, compact lithium-ion battery that helps keep weight gain to a minimum.
  • Automatic centrifugal compression release system on the exhaust cam lifts one exhaust valve to facilitate starting. The system’s simple construction is light weight and highly reliable
  • NOTE: Only use Lithium-ion specific battery charger to help prevent fatal battery damage.


Easy DFI Tuning

  • Riders can change DFI settings by simply replacing a coupler located on the right side of the steering stem. Riders can choose between Standard, Hard or Soft terrain settings to suit riding conditions.


Hand Held Easy-to-Use KX FI Calibration Kit (Optional)

  • Accessory KX FI Calibration Kit features a hand-held controller that enables users to adjust engine characteristics trackside simply by plugging the controller into the engine’s ECU.
  • The kit’s user interface is easy to understand and easy to use.
  • Seven different maps come loaded on the controller to adjust the ECU to suit track conditions. Additional maps can be created and stored on the hand held controller, or on a PC with data transfer between the controller and PC performed via SD card.
  • When connected to the ECU, the controller can be used to display the status of a running engine.
  • Can be used on all KX™ models equipped with DFI.


Launch Control Mode

  • Similar to the system used on the Monster Energy® Kawasaki factory racers, allows riders to activate a separate engine map designed to assist them get holeshots in live-engine starts by pressing a button.
  • The Launch Control Mode map retards ignition timing, allowing the tire to gain grip in low traction situations, and allowing riders to focus on their lines.
  • Even for top-level riders, controlling the massive power of the KX450X off the start requires throttle control and clutch finesse. By slightly reducing this power, Launch Control Mode helps riders maximize traction and increase the chance of getting a good start.
  • Launch Control Mode has the greatest effect within the first few seconds of releasing the clutch off the start – the most crucial time to get ahead of rivals for better positioning going into the first corner.
  • Activated when the engine is running by pressing and holding the launch control button, located at the left handlebar, for two seconds or more while in neutral, first or second gear. When activated, the indicator lamp next to the button flashes quickly to let the rider know the system is engaged.
  • The system automatically disengages when the transmission is shifted into third gear, switching back to the normal engine map.
  • The Launch Control Mode indicator light also serves as a warning light if the DFI system malfunctions.


Aluminum Perimeter Frame (KP)

  • The engine is used as a stressed member, contributing to the frame’s rigidity balance.
  • Steering head area with optimised rigidity, main frame rails, and line for the swingarm brackets contribute to the overall rigidity balance. Wide lower frame rails also contribute to overall rigidity balance.
  • Down tube combines a forged front portion with cast aluminum rear piece which contributes to better front-end feel.
  • Composed of a combination of forged, extruded and cast parts, the aluminum frame is designed with a balance of torsional and longitudinal rigidity for quick handling.
  • Design emphasis on providing maximum traction under acceleration. Specific chassis dimensions and design (reinforcing ribs, swingarm pivot, output shaft, linkage mounts and rear axle) placed to prevent chassis squat and improve traction.


SHOWA 49mm Coil-Spring Fork with A-Kit Technology

  • Equpped with several items developed in SHOWA’s A-Kit premium aftermarket performance kit fork.

– Large-diameter inner tubes –the same size used on Kawasaki’s factory racers –allows large 39mm compression damping pistons and a 25mm cartridge cylinder to be used for smooth action and firm damping.

– The inner surface of the outer fork tubes have Showa’s Dimplush™ texture, which features a wave-like finish to help retain an oil film for smoother action. The Dimplush texture also has Kashima coating to create a hard, low-friction surface that helps prevent wear so the sliding surfaces remain smooth for a long time. The lubricating material in the coating contributes to smoother suspension action, especially at the initial part of the stroke, and a better ride feel.

– Low-friction fork oil further reduces friction.

– Hard titanium oxide coating on the outer surface of the inner fork tubes helps prevent wear, scratches and other damage to the tubes while reducing stiction and improving overall fork action.

  • Based on feedback from Kawasaki’s factory race teams, the 22mm front axle enhances front-end traction.


New Uni-Trak® Rear Suspension

  • Compact designed rear shock has larger diameter compression adjuster that helps prevent oil cavitation under high frequency movement and is equipped with items from Showa A-KIT shock technology.
  • New Uni-Trak rear suspension linkage ratios selected to suit the chassis. The linkage mounts underneath the swingarm allowing additional rear suspension travel yet maintaining a low seat height. The additional rear travel offers improved suspension action over a wider range of track conditions.
  • Dual compression adjustability allows high speed and low-speed damping to be tuned separately.
  • The inside of the shock reservoir has a self-lubricating alumite coating that helps prevent wear abrasion and reduces friction for smoother suspension action.


Big Brakes

  • 270mm Braking brand petal front brake disc provides superb stopping power.
  • Front brake master cylinder provides superb initial control while contributing to overall braking performance.
  • 240mm Braking brand petal rear brake disc for strong stopping power and enhanced rider feedback and feel, beneficial in longer off-road races where endurance is tested.
  • Petal disc shape helps remove dirt build up in pads, increasing performance.


A smooth, flat rider interface provides easy rider mobility on the bike.

  • Equipped with 1-1/8 inch Renthal aluminum Fatbar handlebar that helps reduce vibration and shocks transmitted to the rider as well as optimizing the riding position.


Slim, Adjustable Ergonomics

  • Wide footpegs provide firm footing.
  • Bodywork is designed to facilitate rider movement with long, smooth surfaces that ease sliding back and forth on the bike.
  • The top of the fuel tank is designed to provide a flat progression from the seat to the tank, giving riders great freedom of movement and allowing them to sit far forward.
  • Radiator shrouds are positioned close to the frame so they are slim where the rider’s knees make contact, and the single-piece design make them easy to grip with the legs.
  • The radiators are turned inward 10 degrees, and combined with the narrow frame spars provide a narrow rider interface.


ERGO-FIT® Components

  • Upper triple clamp provides two mounting positions for the reversible handlebar clamps so that the Renthal handlebar can be set in one of four positions with a 35mm range of adjustment.
  • The footpeg brackets can be mounted in two positions, allowing the rider to change footpegs height by 5mm.


Factory-style Details

  • Gold finish on the oil filler, flywheel nut cap and timing inspection cap contribute to factory looks.
  • Black wheels, triple clamps, and cylinder head covers complement Kawasaki’s racing lime green color.
  • Lightweight magnesium clutch, generator and cylinder head covers.
  • Optional parts available through Kawasaki dealers include rear sprockets, solid brake discs, handlebar holder for 7/8” handlebar, and stiffer or softer shock springs.
  • The KX graphics use an in-mold process to seal the graphic into the shroud plastic for greater longevity and an ultra-smooth outer surface.






2021 Kawasaki KX450X – Totalmotorcycle.com USA Specifications/Technical Details
US MSRP Price: $9599  USD
Canada MSRP Price: $10699 CDN
Europe/UK MSRP Price: £ See Dealer GBP (On The Road inc 20% Vat)

Engine Type 4-Stroke, Liquid Cooled, DOHC, 4-Valve, Single Cylinder
Displacement 449 cc
Bore & Stroke 96.0 x 62.1 mm
Compression Ratio 12.5:1
Fuel System DFI® w/ Keihin 44mm Throttle Body
Ignition Digital DC-CDI
Transmission 5-Speed
Rake/Trail 27.6˚/4.8 in.
Front Wheel Travel 12.0 in.
Rear Wheel Travel 12.1 in.
Front Tire Size 80/100-21
Rear Tire Size 120/80-18
Front Suspension 49mm Inverted Coil-Spring Fork
with 16 position compression and rebound damping adjustment
Rear Suspension NEW Uni-Trak® with Adjustable Preload, 19-Position (Low Speed)/
4-turn Stepless (High Speed) Compression Adjustment,
22-Position Rebound Damping Adjustment
Wheelbase 58.5 in.
Front Brake Type 270mm Disc
Rear Brake Type 240mm Disc
Fuel Tank Capacity 1.64 gal.
Ground Clearance 13.2 in.
Seat Height 37.4 in.
Weight Without Fuel 235.8 lb.
Curb Weight= 246.0 lb.
Specifications subject to change without notice.
Ask about Kawasaki’s Team Green™ amateur rider support program.
(KP) = See Kaw-Pedia section for more details.
* = Changes from previous model year.
= = Includes all necessary materials and fluids to operate correctly, full tank of fuel (more than 90% of capacity) and tool kit (if supplied).



2021 Kawasaki KX450X – Totalmotorcycle.com  Canadian Specifications/Technical Details
Engine 449cc, liquid-cooled, 4-stroke, DOHC 4-valve single
Bore x Stroke 96.0 x 62.1 mm
Compression Ratio 12.5:1
Fuel System Fuel injection: ø44 mm x 1
Ignition Digital DC-CDI
Starting Electric
Lubrication Forced lubrication, semi-dry sump
Transmission 5-speed, return
Clutch Wet multi-disc, manual
Final Drive Chain
Frame Perimeter, aluminum
Front Suspension / Wheel Travel ø49 mm inverted fork with adjustable compression and rebound damping / 305 mm (12.0 in)
Rear Suspension / Wheel Travel New Uni Trak with adjustable dual-range (high/low-speed) compression damping, adjustable rebound damping and adjustable preload / 307 mm (12.1 in)
Rake / Trail 27.6° / 120 mm
Steering Angle (L/R) 42° / 42°
Front Tire 80/100-21 51M
Rear Tire 120/90-18 65M
Front Brake Single semi-floating ø270 mm petal disc with dual-piston caliper
Rear Brake ø240 mm petal disc with single-piston caliper
Dimensions (L x W x H) 2,185 x 820 x 1,265 mm (86.0 x 32.3 x 49.8 in)
Wheelbase 1,485 mm (58.5 in)
Road Clearance 335 mm (13.2 in)
Seat Height 950 mm (37.4 in)
Curb Mass** 111.6 kg (246 lb)
Mass Without Fuel 107.0 kg (236 lb)
Fuel Capacity 6.2 litres





2021 Kawasaki KX450X – Totalmotorcycle.com European Specifications/Technical Details





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