Kawasaki’s new KX450F boasts significant engine mods and a new chassis in an effort to leave its competition seeing green.
It would be safe to say that since the departure of Ryan Villopoto, Kawasaki hasn’t been enjoying the best seasons in AMA motocross and supercross competition, but with significant updates to its 2016 KX450F, Team Green may soon return to the top of the 450cc motocross mountain.
For 2016, Kawasaki started at the heart of the big KX, its fuel-injected DOHC four-stroke engine, which features new cases that are designed to be lighter yet stronger and more rigid than the 2015 model. Kawasaki also moved the oil scavenger pump from the left case to the right case for 2016.
Up top, the cylinder head features new, smoother intake ports that are finished with a special coating to give the incoming air/fuel mixture a straighter shot into the combustion chamber. The head’s 36mm titanium intake valves are also new, mimicking the design parameters of the intake valves in its supersport engines. In an attempt to gain better low-end power, Kawasaki engineers also revised the intake cam timing.
The 2016 KX450F’s bore and stroke are the same as the 2015’s at 96mm and 62.1mm respectively, but a new version of the F1-style bridged-box bottom piston has been fitted with a top that matched the new valve shape. The KX’s cylinder is offset, forward 8.5 mm to reduce friction by reducing piston to cylinder wall thrust, which frees up even mor power. Kawasaki also reshaped the crankshaft shaved 1.9 oz. of weight, while the counterbalancer gears have also been lightened to reduce reciprocating weight by 1.4 oz. Less reciprocating weight equals more power.
The KX450F’s new airbox draws fresh air under the seat through scallops in its new rear fender.[/caption]In an attempt to maximize air flow into the engine and improve throttle response, the KX450F’s air box has been completely redesigned. It now brings in fresh air through a pair of air intakes located at the back of the seat. To shave even more weight from the complete package, Kawasaki eliminated all steel parts from the air box structure, which is also claimed to help reduce intake noise.
Fueling upgrades include a more compact fuel injector and a revised fuel pump that facilitate the use of a lower fuel tank to improve the 2016 KX450F’s CG, and the exhaust system gets a new header design with a resonator in an effort to further improve low-end grunt and reduce sound emissions at the same time.
The KX450F’s ECU still incorporates Kawasaki’s launch control, and the ignition curve can be altered by plugging one of three distinct DFI couplers to suit the booming motor to match track conditions and/or riding style. The engine ECU is also fully programmable through Kawasaki’s Accessory KX FI Calibration Kit, a handheld unit that does not require the use of an external computer to facilitate changes to the ignition mapping. The calibration unit can store up to seven preset maps.
Lighter is often faster, and Kawasaki has put the 2016 KX450F on a strict diet, shaving 7.5 pounds of weight compared to the 2015 KX450F. Kawasaki claims the 2016 model hits the scales at 239.6 pounds with its 1.66-gallon fuel cell completely topped off.
A good chunk of that weight, about 1 lb., savings comes in the form of a new aluminum perimeter frame with 6mm slimmer spars than the 2015’s frame. The subframe features thicker walls for improved strength, but the KX’s revised aluminum swingarm, drops another 7.8 oz. while also boasting improved rigidity.
The 2016 KX450F features updates to its Showa suspension as well. Up front, a revised Showa Separate Function Fork, Triple Air Chamber (SFF-TAC) boasts new low-friction seals and updated valving. The left fork leg offers 22 positions of compression damping adjustment and 20 positions of rebound damping adjustment while further fine tuning is possible by adjusting the three air chambers in the right fork leg with the 0-300 psi digital air pump that is supplied with the machine. Out back, the KX’s Uni-Trak rear suspension system uses revised linkage ratios to work in concert with the new chassis. Its Showa piggyback reservoir shock features is adjustable via 19 positions of low-speed compression damping, 4 turns of high-speed compression damping and 19 positions of rebound damping. Typical of most off-road and motocross machines, the spring also features spring preload adjustability.
The 2016 also features revised ergonomics thanks to a flatter seat design and a lowered 1.66-gallon fuel tank, which opens up the cockpit for easier rider movement. Other updates include a lighter front fender, slimmer radiator shrouds, a flatter seat and a resin skid plate to better protect the engine cases..
Perhaps the best news for Kawasaki fans is that the 2016 Kawasaki KX450F offers all of this refinement at a price that is only $100 more than the previous model. MSRP for the Kawasaki KX450F has been set at $8,799.
For more information on the 2016 Kawasaki KX450F, check out www.Kawasaki.com
2016 Kawasaki KX450F Specifications
Engine: Liquid-cooled, fuel-injected, DOHC, four-stroke
Bore x Stroke: 96 x 62.1mm
Compression Ratio: 12.8:1
Fuel System: DFI® with 43mm Keihin throttle body
Ignition: Digital DC-CDI
Final Drive: Chain
Frame: Aluminum perimeter
Rake/Trail: 28°/4.9 inches
Fuel Capacity: 1.66 gallons
Front Suspension: 49mm Inverted Showa SFF-Air TAC Separate Function front Fork with Triple Air Chamber, DLC coated sliders, 22-position compression and 20-position rebound damping adjustment, 12.2 inches of travel
Rear Suspension: Uni-Trak® linkage system and Showa shock, 19-position low-speed and 4-turns high-speed compression damping, 22-position rebound damping and fully adjustable spring preload, 12.4 inches of travel
Front Tire: 80/100-21
Rear Tire: 120/80-19
Front Brake: Single semi-floating 270mm Braking petal-style disc with dual-piston caliper
Rear Brake: Single 240mm Braking petal-style disc with single-piston caliper
Overall Length: 86.4 inches
Overall Width: 32.3 inches
Overall Height: 50.8 inches
Ground Clearance: 13.6 inches
Seat Height: 37.8 inches
Claimed Curb Weight: 239.6 lbs.
Wheelbase: 58.9 inches
Fuel Capacity: 1.66 gallons
Color Choices: Lime Green