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Bryan Bosch

The new Kawasaki KX450F packs more power, better handling and less weight to provide the quickest path to the race podium


June 2, 2015 – (Motor Sports Newswire) – Forty years of Kawasaki KX™ racing tradition, innovation and championship pedigree can be summarized in one word: Proof. Whether it’s claiming 32 AMA Supercross titles, a plethora of wins in media shootouts, or the bike ridden by legends such as Ryan Villopoto, Jeremy McGrath, Jeff Emig, Jeff Ward and Ricky Carmichael – riding a KX motorcycle is the quickest path to a podium. The proof? It’s verifiably the most successful supercross and motocross bike from any manufacturer.




As the flagship of the KX fleet, the Kawasaki KX™450F motorcycle is the most successful 450cc motocross bike available on the market today. This powerful, agile and technologically advanced machine is built for today and tomorrow’s champions. More than simply race-ready, the KX450F motorcycle is like having factory support at your fingertips. It is the most advanced motocross bike Kawasaki has ever produced and is backed by the industry-leading Team Green™support network that can be found trackside, with plenty of suspension advice and even engine settings.
The KX450F motorcycle is completely new for 2016, to give riders the sort of advantage the competition might consider unfair.
Kawasaki is not sitting on its laurels, giving the engine more power and 7.5 lb less weight than before. In fact, the entire motorcycle has seen a significant weight reduction thanks to the redesigned engine as well as a new aluminum perimeter frame.


Riders will also enjoy the improved rider adjustability as well as electronic upgrades aimed at maximizing performance for a variety of riders in any situation while giving the rider supreme confidence.



  • NEW Among the lightest curb weights in class after a 7.5 lb overall weight reduction
  • NEW Lighter, more powerful engine with new engine cases
  • REVISED Bridged-Box bottom piston based on AMA factory race bikes
  • REVISED Intake port improves performance in mid-to-high RPM range
  • REVISED Intake valve shape increases air volume
  • NEW Intake camshaft is lighter and has revised timing for low-mid RPM response
  • NEW High-flow airbox with rear intake channels improve flow and reduce noise
  • NEW Header with integrated resonator chamber for crisp throttle response
  • NEW Mass-centralizing exhaust muffler to reduce sound and weight
  • Plug & play DFI® couplers allow easy engine map changes
  • NEW Slimmer, lighter perimeter frame and swingarm improve rider feel
  • Launch control based on factory race bike system
  • Industry-leading Showa SFF-Air TAC fork and Uni-Trak rear suspension
  • NEW Aggressive factory styling and flatter seat for easier rider movement
  • 4-way adjustable handlebar and 2-way adjustable footpegs fit a wide range of riders

Kawasaki’s already powerful flagship motocross bike is even stronger for 2016, with the KX450F motorcycle boasting a more powerful and lighter engine. The revisions are extensive and start with new engine cases to save weight while optimizing the design to increase strength and rigidity. The location of the oil scavenger pump was also changed, swapping from the left case to the right case.




The cylinder head updates include revisions to the intake ports, which are less curved than before, improving mid-high RPM performance and over-rev. The intake port cores are also given a special coating during the head casting process to make the ports smoother. The extremely smooth surfaces and revised port shape increase the intake efficiency and performance at
all RPM.


The 36mm titanium intake valves have a revised head area. The new design, with slimmer throat angle and reduced recess (similar to valves on Kawasaki supersport engines) contributes to increased high-RPM performance. Revised intake cam timing (advanced 2-degrees) contributes to better low-RPM performance, while the camshaft is 0.5oz lighter than before. A new intake camshaft sprocket is 0.7oz lighter.


The single cylinder is offset (8.5mm forward) to reduce mechanical loss through friction from the piston movement, enabling more efficient power generation. This necessitated a revised crankshaft shape, corresponding to the revised crankshaft housing. The crankshaft balancer shape was also changed – reducing its size and lightening it by 1.9oz. Further updates were made to the crankshaft balancer drive gear and driven gear, resulting in a combined reduction of 1.4oz.
A new crown design for the Bridged-Box bottom piston is based on the AMA factory race bikes and matches the new intake valve shape as well as contributing to the 12.8:1 compression ratio.


Another addition for 2016 is the redesigned air box, which does away with any steel parts, resulting in a weight savings of 8.8oz. It also utilizes new underseat intakes at the back of the seat. These and the revise shape of the air box help to ensure clean airflow, improving engine response and reducing intake sound to meet local market requirements.


Changes were made to the throttle to reduce vibration. This resulted in a new compact fuel injector being used. The outer part of the fuel pump was also revised, changing the flange position in order to lower the fuel tank position, contributing to the motorcycle’s overall lower center of gravity.


Further upgrades include a new exhaust system. It starts with a new header design that features a resonator to improve low RPM power and help reduce the sound level.
The result of these changes to the powerplant mean increased power. And when combined with a lighter overall curb weight, the 2016 Kawasaki KX450F motorcycle has an improved power-to-weight ratio that provides improved acceleration response.


Another weight saving measure saw 9.2oz trimmed from the transmission gears and shafts, which retain their overall strength while contributing to the motorcycle’s dynamic performance. Finally, the shape of the kickstarter has altered, resulting in a saving of 2.6oz.


With all these engine changes, the revolutionary and popular DFI® couplers are again available for the Digital Fuel Injection system. Three are supplied with each motorcycle and allow the riders to quickly change the fuel injection mapping to suit any riding condition. The four-pin DFI couplers are designed for standard, hard or soft terrain settings. The rider simply connects the appropriate coupler cap to suit the track conditions and the DFI couplers immediately activate an ignition mode to match.




The KX450F motorcycle’s Launch Control System is another popular feature that helps obtain holeshot supremacy for the amateur and pro rider alike. The push-button activation retards ignition timing in first and second gears, helping to maximize traction off the line. Once the rider shifts into third, normal ignition mapping is resumed and full power returns.
As a further benefit of owning a KX450F motorcycle, the engine ECU remains fully programmable thanks to the new handheld Kawasaki Accessory KX FI Calibration Kit. This portable device allows custom maps to be created giving riders precise adjustment of fuel and ignition settings. This new handheld module eliminates the need for a trackside laptop computer. It can store up to seven preset maps and is PC-compatible.


Kawasaki’s engineers worked tirelessly to improve handling and chassis feedback with a new aluminum perimeter frame. The perimeter spars are 6mm slimmer than the previous frame, allowing easier rider movement. It is also lighter by 1 lb, while the subframe (seat rails) has thicker walls for increased strength. Overall rigidity has been improved with a new swingarm (while losing 7.8oz in the process), helping rear-wheel traction and rider feel.




The alloy swingarm has a cast front section and twin tapered hydro-formed spars in a raw aluminum finish. Forged chain adjusters are also fitted with a self-locking rear axle nut. The axle nut holds the 80 lb-ft torque setting without the need of a cotter pin for ease of maintenance at the track.


The original goal was to create the lightest motorcycle in its class, increasing the bike’s agility and helping to reduce rider fatigue, making the KX450F more potent than ever before. Following extensive engine and chassis revisions, the 2016 Kawasaki KX450F motorcycle has seen a significant 7.5 lb reduction in curb weight (including fluids), giving it a total weight of 239.6 lb.


Weight savings from the engine group (including intake and exhaust systems) amounted to approximately 4.4 lb, with savings from chassis components totaling approximately 3.1 lb. Some of the major contributing component weight savings include:

  • crankcases (left/right) – 13oz
  • transmission – 9.2oz
  • air filter – 8.8oz
  • frame – 14.1oz
  • suspension (front/rear) – 10.9oz
  • swingarm – 7.8oz

The 2016 KX450F motorcycle receives all-new bodywork with aggressive styling to suit its heightened performance. The minimalist bodywork is light and features angular styling for the new number plates, shrouds, fenders, skid plate and water pump guard. The new bodywork unifies the radiator shroud and side covers for a smoother, seamless rider interface that is 1.2” slimmer at the widest point, and allows unimpaired movement around the motorcycle. The radiator was reshaped in order to achieve this, creating a vee-shape and allowing the shrouds to be slimmer.




The top of the fuel tank is lower than before, allowing easier progression from the seat to the tank. The flatter design gives the rider greater freedom of movement when changing riding position, while also allowing the rider to sit further forward.




The appearance is further highlighted by green engine plugs, oil cap and generator cover plugs, as well as green alumite suspension adjusters and black alumite wheels. Another neat detail is the embossing on the clutch cover, which was designed to gradually appear as contact from the rider’s boots wears away the paint. A new generator cover has also been incorporated to fit the new crankcase.


To protect the 2016 Kawasaki KX450F motorcycle from general wear and tear encountered during a typical day at the track, a large synthetic skid plate offers great protection with minimum weight. The revised design has oval holes that facilitates easy mud removal and reduces the weight further.


With Kawasaki engineers creating a lighter motorcycle, its agility was increased, allowing the suspension and brakes to work more efficiently and effectively. This is especially true of its state-of-the-art Showa SFF-Air TAC (Separate Function front Fork, Triple Air Chamber) fork technology, which separates the damping and shock absorption duties into the individual fork legs. The left fork tube contains the damping assembly and the right fork tube contains the air spring. Instead of the steel coil springs found in conventional forks, the SFF-Air TAC’s right fork tube has three chambers filled with pressurized air that act as a “spring”. Eliminating the steel coil springs reduces friction by approximately 20% and creates an extremely smooth action throughout the fork’s stroke. This has the added benefit of greatly reducing weight and allowing a larger damper piston to be used, providing smoother action. New low-friction fork seals and revised valve settings for reduced damping deliver easier fork movement, matching the pitching characteristics to the lighter chassis.


Aggressive styling for the new front fender adds to the motorcycle’s overall racy appearance and also saves 1.8oz in weight overall the previous model year.




This works-replica fork is derived from Kawasaki’s factory race bike. It is lightweight and rigid, contributing to superior riding stability and front-end feel. The low friction design contributes to an extremely smooth fork action, while precise settings are possible merely by changing air pressure.


The fork has traditional 22-position compression and 20-position rebound damping adjustment. Furthermore, the rider can adjust the internal air pressure with the Kawasaki Genuine Accessories 0-300psi Digital Air Pump that is supplied with the KX450F motorcycle. Changing the air pressure covers a range of settings offered by optional springs in a standard fork, including quick changes of ride height, without needing to disassemble the fork tubes. The pump’s digital display offers precise air pressure setting, and its casing stores the engine’s DFI couplers for the fuel injection system, allowing better organization on practice or race days.


New linkage ratios for the Kawasaki Uni-Trak® suspension system were designed to suit the new aluminum frame and swingarm. Mounting the link below the swingarm allows a longer rear suspension stroke, while maintaining a low seat height. Dual compression adjustability from the Showa shock allows high-speed and low-speed damping rates to be set separately. The shock reservoir has a friction-reducing internal Kashima Coat for improved suspension action. This race-oriented suspension offers class-leading action and adjustability on par with the Showa SFF-Air TAC fork. The fully adjustable unit allows for precise settings to help keep the rear wheel planted and the rider out front.


Riders looking for an extra edge over the competition can use the optional Kawasaki rear suspension tie rod. It is 1mm longer than stock and can be used to reduce seat height by 4mm to give the rider greater control and adjustment.


Being able to enter every corner at the desired speed is critical to fast lap times. The 2016 Kawasaki KX450F motorcycle uses an oversized 270mm, petal-shaped front brake rotor (largest in class) from the renowned manufacturer, Braking. It helps provide powerful stopping forces, good lever feel and consistency in all conditions. It is paired with a 240mm petal-shaped Braking rotor on the rear.


Kawasaki’s commitment to the rider continues with an adjustable handlebar and footpegs to fit various sizes and riding styles. The footpegs feature dual-position mounting points, with a lower position, which reduces the height from the standard position by an additional 5mm. The lower position effectively lowers the center of gravity when standing, and reduces knee angle when seated.




The handlebars offer 4-way adjustable mounts. With 35mm of range, the multi-position handlebars feature two mounting holes, andthe 180-degreeoffset clamps provide four individual settings to suit different size riders.


Equipped with a flat seat, adjustable footpegs and handlebar as well as fully adjustable suspension, the 2016 Kawasaki KX450F motorcycle can be tailored to suit a large range of riders. This perfectly complements the wide range of damping settings as well as the DFI couplers and optional handheld Kawasaki Accessory KX FI Calibration Kit, allowing the rider to find the ideal engine characteristics to suit a particular track or conditions. So while the base settings on the KX450F motorcycle are based on extensive testing, including racing, the motorcycle provides a huge range of technology and adjustment to help ensure every rider can fully exploit the incredible ability of this extremely capable motocross bike.

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This bike is sick i bought one and it handles nothing like the older kx450fs... it feels much lighter than it is too..

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