Forget about Ryan Villopoto’s four AMA Supercross Championships on a Kawasaki. Although impres- sive, those wins on a special hand-built machine
mean very little to the local racer. But, what does count
is the KX450F’s and KX250F’s incredible string of MXA
250/450 shootout victories. This is where the pudding is—
and where the proof is found.
The 2015 Kawasaki KXs rise to another level with more
adjustability as well as chassis, suspension and brake
11 NEW THINGS ON THE 2015 KX450F
1. Last year’s Kayaba PSF air forks have been replaced
by Showa Separate Function Forks (SFF) with a Triple Air
Chamber (TAC) that separates the damping forces into
the left fork tube, while the pneumatic spring is housed
on the right tube for less friction, better movement and
a lighter fork. The Triple Air Chamber features three
separate chambers with individual air volumes that
allow for the ultimate in adjustability. An inner, 145-psi,
high-pressure pneumatic chamber works in harmony with
a 7.25-psi, low-pressure outer chamber and a 130.5-psi,
high-pressure lower chamber. These replace the heavy,
friction-inducing coil springs of a conventional fork.
2. Every 2015 KX450F comes with a free 0- to 300-
psi digital air pump to help riders quickly adjust their
high-pressure SFF-Air TAC forks. The digital display offers
increased precision when setting air pressures.
3. Out back, the Showa shock has revised valving for
firmer damping. The Kashima coating inside the shock
body reduces friction and improves suspension action.
Kawasaki also offers an optional 1mm-longer shock link to
reduce the seat height by 4mm.
4. The revised Bridged Box piston offers increased
durability and a higher compression ratio ( 12.8:1 from
12.5:1 in 2014). The cutting-edge piston design was pulled
straight from the factory race team and features short
skirts with reinforced external ribs to improve combustion
efficiency and reliability.
5. The ECU system was revised for 2015 with new
programming to enhance traction by retarding the
ignition when rear-wheel speed increases too quickly
(from sudden, excess wheelspin). This is best known
as traction control.
6. Launch Control returns for 2015. The push-button
activation retards ignition timing in first and second
gears, which, in turn, maximizes traction. Once the rider
shifts into third, normal ignition mapping is resumed and
full power returns.
7. Kawasaki has upped the ante for 2015 with a
270mm, oversized, petal-shaped front brake rotor to
replace last year’s 250mm front rotor. It is paired with a
240mm Braking rear rotor.
8. The KX450F shares a lighter rear subframe with
the KX250F. It reduces the weight and improves mass
centralization for a more nimble feel.
9. Gone is the castle nut on the rear axle, and in its
place is a self-locking rear axle nut. The design holds 80
foot-pounds of torque (without the need for a cotter pin).
10. The axles are new for 2015, lightened by 31 grams
front and 32 grams rear.
11. The 2015 KX450F look is highlighted by factory-style
graphics, green engine, oil cap and generator plugs, green
alumite suspension adjusters and black alumite wheels.