Home Bike Review Kawasaki Announced 2017 KX450F and 250F Models

Kawasaki Announced 2017 KX450F and 250F Models

Kawasaki KX450F Frame
Kawasaki KX450F

Kawasaki KX motocross lineup is the most successful motocross and supercross brand of motorcycles on the market today. This year, the KX450F attention with a new frame, engine layout, and many other changes.

The highlights of the KX250F are as follows:

It is claimed to be lighter at 104 Kg (229.9 pounds) and Lighter frame.

Kawasaki KX450F Frame
Kawasaki KX450F Frame

New seat and plastics

New swing arm

ECU (engine control unit) that is lighter and includes three riding modes.

Speaking of, Kawasaki KX changes are less pronounced and include the following:

The following is all the information that we have from Kawasaki.

Lighter weight 104 Kg (229.9 pounds)

  • New more powerful and lighter engine
  • New redesigned more narrow and lighter weight frame
  • Improved clutch and shift feeling
  • New flatter seat and a new lower/flatter tank, for improved handling and ergonomics

This year’s KX250F is built with race-winning components to keep Kawasaki riders in that top spot at the race track. From the showroom to the racetrack, the performance of Kawasaki’s KX family of motorcycles is proof of its engineering pedigree. It truly is the bike that builds champions.


  • New redesigned engine with offset cylinder layout, for more efficient power
  • Lighter bridged-box bottom piston, designed from racing experience
  • Downdraft-style intake layout with new injector angle designed for optimum fuel atomization
  • New downstream injector with twice as many holes, finer fuel droplets, and wider angle, resulting in stronger low-to-mid power and sharp response
  • New and improved combustion chamber configuration
  • New 43mm throttle body

Tuned to best suit race-experienced riders, the 249cc liquid-cooled, 4-stroke single’s wide power-band focuses on high-rpm performance that extends way into the over-rev. Highly acclaimed for its high output and smooth power delivery, the 2017 model KX250F has race-inspired tuning and parts like the high-performance bridged-box bottom piston and down draft-style intake routing. Mechanical friction is reduced thanks to things like an offset cylinder—with increased forward lean angle—and plateau honing, resulting in a stronger low end as well as an increase in maximum peak power. The connecting rod now features a journal bearing in lieu of a needle bearing and items like the camshaft sprockets and chain have been revised along with a newly revised exhaust camshaft, all factors resulting in more efficient power.

The KX250F dual-injector fuel injection system is a key component to its performance; introduced in 2012, it was the world’s first to be featured on a production motocross bike. Unlike a standard digital fuel injection that uses one injector downstream of the throttle valve, the KX250F system uses a second, upstream injector located close to the airbox. The downstream injector—redesigned for 2017—is used to help ensure smooth, instant response featuring a finer atomization with more holes in the injector itself. The downstream injector creates that stronger low-to-mid range power and quick throttle response, while the upstream injector is charged with providing power.

As rpm and throttle position increase, primary operation switches from the downstream injector to the upstream injector, depending on whether in a low (1st, 2nd) or high (3rd, 4th, 5th) gear, the transition is gradual or almost instantaneous. The upstream injector’s greater distance from the combustion chamber gives the fuel particles and intake air more time to mix, as well as allowing the mixture to cool before entering the combustion chamber, both of which contribute to more efficient filling, and ultimately more power. The 2017 model also features revised ECU settings, along with a new exhaust system. The exhaust header pipe is skinnier and shorter, resulting in improved performance.


  • Lightweight ECU, with revised settings
  • Three engine maps (standard, hard, soft) contained in the ECU
  • Optional KX FI Calibration Kit (Handheld) requires no tools, laptop or battery

The lightweight ECU of the KX250F motorcycle was designed specifically to withstand the rigors of motocross racing, while still providing a wide variety of tuning. The Kawasaki KX250F provides three engine maps that come pre-loaded into the motorcycle’s ECU that are easily accessible through the DFI® coupling plug. These three color-coded couplers are designed to tune for hard, medium or soft track surfaces, and allow riders to find the perfect power delivery for a particular terrain.

Using the optional KX FI Calibration Kit (Handheld), sold separately as a Kawasaki Genuine Accessory, a rider can store and select from up to seven separate engine maps. The kit includes a portable handheld calibration tool, which enables riders to make changes to the engine maps without the need of a PC, laptop or battery, making it easy to tune at the track. It plugs in thanks to an additional harness not included in the kit.


  • New Swingarm design with improved linkage ratio
  • Lighter weight and more rigid frame design
  • 6mm narrower frame design
  • Showa 48mm Separate Function Front Forks (SFF Type 2)


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