New KX450 Specialist Motocross Race Model Launched - Bringing Together Advanced Technologies Developed on the Racetrack

Jun. 12, 2018


Tokyo, June 12, 2018 – Kawasaki Heavy Industries, Ltd. announced today the launch of the new KX450F, the fully revamped 2019 model of the top-end specialist motocross race motorbike*1. The new KX450 will be sold in Europe, the USA, Canada, Australia, Japan and Brazil, and is planned for release on the Japanese market in summer 2018.

The KX series has put riders in front across the world since its debut over 40 years ago, including Eli Tomac, who rode the KX450F to victory at the 2017 AMA Motocross Championship. With a concept of "taking the rider to the top of the podium," the same advanced technology as the factory racing team’s bikes*2 competing in the AMA Supercross and Motocross Championships and the Motocross World Championship is adopted throughout the KX450, increasing competitive strength in a race.

Based on the lime green that symbolizes the Kawasaki race team, the coloring and graphic design of the KX450 evoke the image of a factory race bike, and give it a sharp and racy appearance.

Main features


1. New engine adopting finger-follower rocker arms
Equipped with a newly-designed four-stroke, single cylinder, DOHC, liquid-cooled 449 cm3 engine. Using designs from Kawasaki World Superbike engineers, finger-follower rocker arms are added to increase the output by approximately 2.5 kW (3.4 PS) over the existing model.
2. Electric starter, hydraulic clutch and lithium ion battery adopted
This is the first time an electric starter and hydraulic clutch have been adopted in the KX series. The electric starter enables a quick restart of the engine in the event of a sudden stall during a race and the hydraulic clutch gives a direct and reliable lever operation. In addition, the motorbike is equipped with a lightweight, compact Li-ion battery to keep weight to a minimum.


1. New frame and swingarm to improve rigidity balance
The lightweight aluminum perimeter frame – an evolution from the previous model – improves the rigidity balance by using the engine as a stressed member. In addition, the rigidity of the swingarm has been revised to match the main frame, increasing traction at the rear wheel.
2. Equipped with large coil spring front forks
The KX450 motorcycle is equipped with new 49 mm inverted coil spring front forks that are the same size as those found on the front suspension of the factory racing team’s bikes. These enable the use of large damping pistons for smooth action and firm damping characteristics. A hard titanium coating on the fork inner tubes and Kashima Coat*3 on the outer tubes help to prevent wear abrasion and to keep the surfaces as smooth.
3. Lightweight chassis and engine components
The weight of components such as the air intake ducting, automatic decompression system and crankshaft has been reduced. While adopting new equipment such as an electric starter, the weight increase is kept to just 1.3 kg over the existing model.
4.  New bodywork design
In addition to a longer, smoother seat form for greater freedom of movement, the flatter and lower fuel tank design allows the rider to sit farther forward.

Primary Equipment

1. Equipped with the same launch control system as the factory racing team’s bikes. An engine map configured for an efficient start on slippery road surface is activated at the press of a handlebar button to give the rider the holeshot*4.
2. Changing the DFI couplers enables the rider to quickly change between three engine maps (standard/soft/hard) configured in the ECU.
3. KX Calibration Kit offered as a Kawasaki Genuine Accessory. The handheld controller eliminates the need for a laptop or external power supply, and gives riders the ability to create custom maps. The kit comes with seven preset engine maps to respond quickly to course conditions.

*1: A race on an off-road course where riders compete for position within a fixed time.
*2:  The motorbikes used by the race team directly managed by a manufacturer.
*3: Hard alumite surface treatment that has been given lubrication functionality (anodic oxidation finish processing for aluminum that increases corrosion/scratch resistance) to make lubricated alumite with improved abrasion resistance.
*4:  Entering the first corner after the race start in the lead. This gives the rider the edge in the race.


Product name KX450
Launch date 12 June, 2018
Region of release Europe, the USA, Canada, Australia, Japan, Brazil
Colors Lime green

The KX450 cannot be operated on public roads or with general traffic. Also, license plates cannot be obtained for the KX450.
Places other than public roads, such as private roads, farm roads, forest roads, riversides, beaches, etc., where people and cars can freely enter and exit are regarded as roads, and operating the KX450 in such locations is in violation of the Road Traffic Act and the Road Transport Vehicle Act.

Main specifications
Product name KX450
Model KX450JKF
Length × width × height 2,185 mm × 830 mm × 1,275 mm
Wheelbase 1,485 mm
Min. ground clearance 340 mm
Seat height 955 mm
Caster/trail 27.6°/122 mm
Engine/valve type Liquid-cooled 4-stroke single cylinder / DOHC 4 valve
Total displacement 449 cm3
Inner diameter x stroke 96.0 x 62.1 mm
Compression ratio 12.5:1
Starting method Electric starter
Ignition method Digital DC-CDI
Lubrication methodSemi-dry sump
Engine oil capacity1.0 L
Fuel supply systemFuel injection
Transmission typeConstant mesh 5-stage return shift
Clutch typeMultiplate wet clutch
Gear ratios
1st1.750 (28/16) 
2nd 1.412 (24/17)
3rd 1.188 (19/16)
4th 1.000 (19/19)
5th 0.875 (21/24)
Primary reduction ratio /
secondary reduction ratio
2.727 (60/22) / 3.846 (50/13)
Frame typePerimeter (semi-double cradle)   
Suspension systemFront Telescopic (inverted)
Rear Swingarm (new Uni-Trak)
Tire sizeFront 80/100-21 51M
Rear 120/80-19 63M
Brake systemFront Single disk 270 mm (outer diameter)
Rear Single disk 250 mm (outer diameter)
Steering angle (left/right)42°/42°
Vehicle weight110.0 kg
Fuel tank capacity6.2 L

Numbers are overseas specifications


If you need more information about our business,
please feel free to contact us.