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2021 Kawasaki KX450X Dirt Motorcycle Review Specs

The brand new 2021 Kawasaki KX450X Dirt Motorcycle is the flagship model of the off-road competitive KX series for 2021. Whether in the jungle, desert, or cross country, the KX450X is a championship-ready machine out of the box, and it shares a lot with people. One of the winning features is its Motorcross sibling, the KX450.

The 449cc Liquid Cold Four-Stroke Engine, Slack Aluminum Perimeter Frame, Shaw A-Cat Technology Suspension, Hydraulic Clutch, and Electric Start are ideal combinations for the more experienced riders of the championship-winning package.

The KX450X is equipped with race-winning components to help Kawasaki riders reach the podium. The performance of the 2021 Kawasaki KX450X Dirt Motorcycle is a testament to its engineering prowess from showroom to race track.

2021 Kawasaki KX450X Dirt Motorcycle

Kawasaki motorcycles have expanded their off-road lineup with the new KX450X. Kawasaki brand has a long history of off-road racing. The new cross-country racer maintains the KXTM450 motocross racer’s championship-winning performance and factory-style equipment but with X-specific engine tuning and suspension settings, 21/18-inch wheels with enduro-type tires. It Includes practical standard features like a side stand and skid plate.

2021 Kawasaki KX450X Dirt Motorcycle – Features and Specs

Unique Key Features

  • All new engine and suspension settings are designed for off-road use.
  • Brand new 18 “rear wheel and 21” front wheel
  • All new GEOMAX AT81 Dunlop tires
  • All new brake components
  • All new skid plate kickstand

KX450X Exclusive Features

Off-road racing is not the same as motor cross/super cross racing. As a result, the KX450X differs from the standard 2021 Kawasaki KX450X Dirt Motorcycle in the following ways.

While the engine of the KX450 motocross racer retains all its power, the fuel injection/ignition programming has been adjusted to offer the best amount of energy used for cross-country racing. Kawasaki Genuine Parts and Accessories KX FI Calibration Kit allows riders to customize power delivery to their unique demands better.

2021 Kawasaki KX450X Dirt Motorcycle

Compared to the KX450 motocross racer, short gearing is better for dealing with off-road courses with a tooth-large rear sprocket, loose rock sections, dirt climbs, root-affected tracks, and other issues requiring lower gearing.

The KX450 motocross racer features a high-performance 49mm Ultimate Coil-Spring Fork and New Unitrack Rear Suspension. However, since cross-country tracks do not have significant motor cross-track jumps, spring rates and damping settings are tuned for off-road racing to provide more feedback, especially on more challenging routes.

Front brake pads are specially designed for off-road use.

The 18-inch off-road rear wheel allows tires to have a large sidewall for smooth riding on rocks and roots, as well as increasing the resistance to the flattening of flats. Dunlop AT81 tires are designed for cross-country riding and provide excellent traction.


The engine produces a lot of power, and the torque curve is flat, making it easy to accelerate and find traction. The finger-follower valve train, which has reduced friction loss and the step-down draft intake tract, was designed by engineers who won the Kawasaki Multimet World Superbike Championship.

4-stroke motor

Lighter pistons reduce each other’s weight and improve engine performance. The piston has a built-in bottom of the bridged-box like factory racers, with fully flush inner braking and a short skirt and strong outer ribs, resulting in a lighter, stronger piston.

To improve performance, the piston skirt is covered with a dry film lubricant to reduce friction between the piston and the cylinder.

Simple bearings on the upper end of the connecting rod help to increase strength by minimizing mechanical damage.

2021 Kawasaki KX450X Dirt Motorcycle

The cylinders are 8.5 mm forward to reduce friction and increase power generation efficiency.

The wedge-shaped crank extends the web of the setting moment, resulting in a balance factor of about 60%, similar to a factory bike. Low engine vibration, smooth power delivery, and improved performance are all advantages of the high balancing factor, especially at low rpm where the response is quite fast.

For better performance and longevity, an aluminum cylinder with chrome composite plating (KP) provides efficient heat transmission, excellent wear resistance, and excellent lubricating material retention.

Race-tuned 4-Valve Cylinder Head (KP)

Engineers who won the famous Kawasaki Multimedia World Superbike Championship designed the Finger Follower Valve Train, which allows large diameter valves, offensive cam profiles, and a high ROP limit for high RPM performance.

Compared to the tapite-style process, the finger follower valve activation valve reduces the bulk of the train by about 6.5% while also reducing the friction in the cam lobe. Followers have a brand new DLC (carbon-like a diamond) coating that helps in preventing wear.

2021 Kawasaki KX450X Dirt Motorcycle

For durability, aggressive camshaft lobes are covered with chromium nitride.

The 40mm and 33mm diameter titanium volume and exhaust valves help reduce weight.

Downdraft Intake

Dow draft style intake routing provides a 20-degree approach angle for direct intake air approach, which improves cylinder filling efficiency and contributes to strength.

The 44mm throttle provides enough air for maximum performance, especially at high rpm and overrun. The butterfly valve is tilted from the top, allowing maximum fuel atomization from the top-mounted injector.

The 12-hole good atomizing injector sprays 75-micron droplets, resulting in smooth power transmission and excellent partial throttle response. Exhaust resonator

Longer header pipes help provide stable low-end power.

The exhaust system includes a resonator chamber to effectively increase the length of the exhaust pipe and reduce the exhaust noise.

2021 Kawasaki KX450X Dirt Motorcycle

Hydraulic clutch with cond disc spring

Instead of five coiled springs, when the lever is pressed, the clutch uses a single-coded disc spring for the lighter clutch operation and a more comprehensive clutch engagement range that helps control the rider. The clutch lever action becomes more delicate as the spring disc of the cond disc falls as soon as it arrives at the lever, which decreases the rider’s fatigue during off-road activities.

Start with electricity

The engine can be started rapidly and easily with the push of a button.

Powered by a highly lightweight, compact lithium-ion battery that helps you lose weight.

The exhaust cam’s automatic centrifugal compression release system increases an exhaust valve to make it easier to start. The simple design of the system is lightweight and reliable.

To avoid fatal battery damage, use only lithium-ion special battery chargers.

DFI tuning made easy

DFI settings can be easily changed by changing the coupler to the right of the steering stem. Riders can choose from three terrain settings according to their riding conditions: standard, hard and soft.

2021 Kawasaki KX450X Dirt Motorcycle – Price

The new 2021 Kawasaki KX450X Dirt Motorcycle is available at $4,599 only.

2021 Kawasaki KX450X Dirt Motorcycle

2021 Kawasaki KX450X Dirt Motorcycle – Technical Specifications


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.

Wheels and Suspension

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

Dimension and Weight

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.

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