Not light and agile by any means, but the KX450F is a stable platform.
( 3) Rear brake pedal. Old-school racers who want to run their
brake pedals low will have to hacksaw off some of the plunger’s
( 4) Ignition. We had some issues.
Q: WHAT DID WE LIKE?
A: The like list:
(1) Traction control. What a happy circumstance that the AMA
changed its traction control rules in time for the 2015 KX450F to
come with it—or was that vice versa? If it is working right, you will
never notice it.
( 2) Launch Control. Use it or not. We run it on concrete and
hard-pack starts but not on loam.
( 3) Rear axle nut. Thank you, Kawasaki, for getting rid of that
stupid cotter pin.
( 4) SFF-Air forks. Hey, we may doubt the wisdom of spec’ing
them, but they are 2 pounds lighter.
( 5) Air pump. Kawasaki gives every KX450F buyer a free 0–300
psi digital air pump. You will wear it out.
Q: WHAT DO WE REALLY THINK?
A: We think that the suspension issues will be worked out
with more testing and a broadening of the SFF knowledge base,
but even then this fork will be a nightmare in the hands of a
less-than-proficient owner. Other than that, everything else on the
2015 Kawasaki KX450F is as good or better than last year’s bike,
which won the “2014 MXA 450 Shootout.” ❏
This is how we set up our 2015 Kawasaki
KX450F for racing. We offer it as a guide to
help you find your own sweet spot.
SHOWA SFF-AIR TAC FORK
Two years ago, Kawasaki and Honda
both switched to Kayaba PSF air forks.
They were workmanlike forks, but
they had fork-seal issues, low-speed
compression problems and weren’t the
best forks ever made. Now, for 2015,
Kawasaki has equipped the KX450F with
Showa’s single-sided SFF-Air fork. Had we
been the product manager at Kawasaki,
we aren’t sure that we would have
green-lighted these forks for a production
bike. They are too hard to set up, too hard
to live with and those problems dominated
For hardcore racing, we ran this setup
on the 2015 Kawasaki KX450F (stock specs
are in parentheses):
Inner spring rate: 178 psi ( 145 psi)
Outer spring rate: 7. 5 psi ( 7. 5 psi)
Balance spring rate: 167 psi ( 135 psi)
Oil height: 340cc (left leg), 100cc (inner
chamber), 300cc (outer chamber), 10cc
Compression: 20 clicks out ( 5 clicks
Rebound: 18 clicks out ( 13 clicks out)
Fork-leg height: 5mm up
Notes: These forks are hard to figure out.
The high air pressures are hard to ensure
with the supplied air pump. Our pressures
varied as much as 7 psi. We hated the
recommended fork settings for everything
except the outer chamber, where they
didn’t make much of a difference.
SHOWA SHOCK SETTINGS
The shock was a surprise. It worked well
from day one, and although we went out
on several settings and ran the race sag
at a relatively low 104mm, we liked the
improvements to the rear suspension.
We recommend this shock setup on the
2015 Kawasaki KX450F (stock specs are in
Spring rate: 5. 5 kg/mm
Hi-compression: 2-1/4 turns out
( 2 turns out)
Lo-compression: 16 clicks out ( 12 clicks
Rebound: 11 clicks out ( 10 clicks out)
Race sag: 104mm
Notes: The shock does not blow through
as easily as last year, which is a big plus.
Additionally, the rear end had a minimal
amount of wallowing and worked very well
under braking in choppy bumps.