2016 Kawasaki KX450F Preview

Kawasaki announced several updates for the 2016 KX450F including a new engine and frame while subtracting 7.5 pounds of weight.

The KX450F’s 449cc Single received new engine cases that are lighter yet stronger and more rigid. The cylinder head was revised with new intake ports that are smoother and more direct thanks to a special coating applied during the head casting process. Kawasaki claims the changes increase intake efficiency, improving performance at all engine speeds, especially at mid-to-high rpm.

The revised 36mm titanium intake valves are now more similar to those used in Kawasaki’s supersport engines, also contributing to high-rpm performance. The intake cam timing was also revised to improve performance at lower engine speeds. The “bridged-box bottom” piston has a new design based on the AMA factory motocross racer, matching the new intake valve shape.

The cylinder is offset, forward 8.5 mm to reduce friction from the reciprocating piston. As a result, Kawasaki also revised the crankshaft shape. The crankshaft balancer was also updated, trimming 1.9 oz. of weight, while the balancer’s drive gear and driven gear are also lighter, saving a further 1.4 oz.

Kawasaki redesigned the air box, getting rid of all steel parts, eliminating a further 8.8 oz. The air box makes use of new air intakes at the back of the seat. According to Kawasaki, the new air box design improves air flow, resulting in better engine response while reducing intake sound.

Other engine updates include a more compact fuel injector and a revised fuel pump that allowed for a lower fuel tank, improving center of gravity. Kawasaki also moved the oil scavenger pump from the left case to the right.

The exhaust system also saw some updates, with a new header design with a resonator to improve low-rpm power while reducing the sound level.

Kawasaki engineers found another 9.2 oz. in weight savings by revising the transmission and an additional 2.6 oz. by changing the shape of the kickstarter.

Kawasaki retains the previous KX450F’s electronics including launch control and three swapable DFI couplers supplied to change ignition mode for standard, hard or soft terrains. The engine ECU is fully programmable via the optional Kawasaki Accessory KX FI Calibration Kit. The handheld unit works without needing a trackside laptop. The kit stores up to seven preset maps for customizing precise fuel and ignition settings.

The Showa Separate Function Fork, Triple Air Chamber (SFF-TAC) suspension returns with new low-friction seals and revised valve settings. The fork offers 22-position compression and 20-position rebound damping adjustment. Three air chambers in the right fork tube can be further tuned by changing the air pressure using Kawasaki’s supplied 0-300 psi digital air pump.

The Kawasaki Uni-Trak rear suspension system gets revised linkage ratios to fit the new frame and swingarm. The Showa shock offers 19-position low-speed and 4-turns high-speed compression damping adjustment as well as 19-position rebound damping and fully-adjustable spring preload adjustment.

The brakes are unchanged from 2015, with a two-piston caliper and 270mm petal brake disc up front and single-piston caliper with 240mm rotor at the rear.