KFX - Dubach Racing Development

ATV FEATURE
FACTORY
PRESCRIBED
BY DR. D
KAWASAKI
By Nick Nelson
Photography By Enrico Pavia
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ATV WORLD MAGAZINE
450R
KFX
recently invited to meet up with
the guys from Kawasaki and
test a KFX450R that Dubach
Racing had recently built into a MX race quad. Never being
one to miss a track day or the chance to ride a professionally prepped race bike, I quickly agreed and made plans for
a Thursday morning at Glen Helen Raceway. Dr.D and the
guys from Kawasaki had built a top notch bike for us, so I
called on my friend Enrico Pavia of Enrico Pavia
Photography to come out and get us some killer images
while we rode it.
We met up early at Glen Helen Raceway to get the run
down on the KFX and then spin some laps. Arriving at the
track, I got a quick reminder that ATV’s are still like the red
headed step children at this Southern California track. While
the handful of motorcycle riders were ripping up the national
I was
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450R
KFX
ATV FEATURE
tapered intake tube. With a new intake
installed, the KFX could now breathe
well enough to complement the rest of
the engine mods. A few passes on the
dyno and a couple of very simple
adjustments to the Mod Box, and the
KFX was ready to impress anyone in
the horsepower department. In order to
harness this added horsepower and
deliver it to the ground reliably, DR.D
installed a bullet proof Hinson Racing
clutch set up that has proven to last the
lifetime of most race ATV’s.
With the motor lined out, the next
thing addressed was the suspension.
The KFX front end is known to be more
than just a little bit on the twitchy side.
A 2.5 inch wider “FLOW” A Arm from
Walsh Racecraft not only widens the
green machine out to a track perfect
49.9 inches, it also changes the front
end geometry, completely getting rid of
any sketchiness at all. This front end,
while available to the public, is the
same geometry developed through
countless hours of testing with the factory racers. Installing longer PEP stainless brake lines was also necessary
after widening the front arms. Race
team testing and development time
was stolen from the factory guys again
when it came to setting up the Fox
Float front shocks and Podium rear.
The beauty of the Fox Float system is
that with no springs to change, the
same shock can be radically changed
by just adjusting the air pressure in the
two different air chambers. After a full
season of testing with this combination, the Kawi guys know exactly where
to set the pressures with this front end
for unbeatable handling. An adjustable
width Lonestar Axcalibur Racing Axle
was used to widen the rear up to MX
specs. The LSR axle carries a full lifetime warranty against bending or
breakage, so it will surely be the only
axle you’ll need for the life of your ATV.
Jimmy White, who was in charge of
the Kawasaki Factory team, had sup-
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caliber motocross track, the quads
were left banished to Thursday practices on the under-prepped and overwatered beginner level vet track. OK…
enough crying over our sport’s second
rate treatment. The DR.D KFX looked
amazing and we couldn’t wait to ride it,
no matter what track they were going
to let us ride. Before hitting the track, I
discussed the what and why of this
great looking KFX with both Dubach
Racing’s “DR.D” and Russ Brenan of
Kawasaki Motors Corp.
Kawasaki had built a very successful
race program around the KFX450R,
and DR.D would utilize most of these
spec’s and parts that had proven successful at the National Race level. The
KFX drastically needs a few things to
really run well. With today’s emissions
laws, every sport quad made will benefit from an aftermarket exhaust, but
with the KFX, the air intake tract is an
equally important problem that needs
to be addressed. The Kawasaki
Factory ATV racers build their practice
motors with nothing more than an
exhaust, a fuel injection programmer, a
fuel custom intake, and a set of cams
from the KXF450R dirt bike. Knowing
that this combo makes for a stellar, yet
super reliable motor package, DR.D
opted to leave the head and compression ratio stock, only installing a set of
08 KXF dirt bike cams. After installing
the cams, DR.D installed a full system
competition series exhaust and a Dr.D
Mod Box tuning module. Next, the bike
made a short trip over to Fuel Customs
for a much needed air box, filter and
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KFX
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ATV FEATURE
450R
KFX
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plied the suspension specs as well as
tons of insight and knowledge to make
this build a success. He also hooked us
up with the new “Bite” MX tires, mounted
on DWT G2 bead lock rear wheels and
DWT rolled lip front wheels. The Bite MX
tires are a lightweight carcass tire with a
tread pattern developed by factory racers
to provide ideal traction in any MX situation, with no grooving necessary.
For the ultimate in control, they opted
for the vibration and shock absorbing tunable Flexx Handlebar system from Fasst
Company, combined with a GPR sub
mount steering stabilizer. The Flexx
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ATV WORLD MAGAZINE
Handlebar system articulates and dampens in the same plane as your suspension, to drastically reduce shock to your
arms and hands without affecting steering control. These bars have adjustable
density elastomers to provide the rider
with exactly the desired amount of resistance. While the bars are designed to
reduce any direct impact shock, the GPR
stabilizer will soak up and eliminate any
negative steering feedback caused by
rough terrain or even clipping obstacles
with your tires. This combination of
impact absorbing handlebars and top
notch steering stabilization allows the
rider/racer to ride harder
and longer as well as preventing incident. To help
this KFX stop as well as it
goes, Fasst Co. also provided a billet brake clevis
and their Brake Pedal
Return Kit. The clevis is
designed to not only look
really trick, but also utilize
hardened pivot pin and
bushing, eliminating any
play or slop felt in the
brake pedal. The spring
kit is a newly developed
part that eliminates your
stock brake pedal return
spring, offering tunable
pedal resistance and just
plain better overall feel at
the brake pedal.
TORONTO SNOWMOBILE, ATV AND POWERSPORTS SHOW. OCTOBER 15, 16, 17 • TORONTO INTERNATIONAL CENTRE • www.torontosnowmobileatvshow.com
To finish off the build, they installed
the same black powder coated DG
Factory Double Net nerf bars and DG
National II bumper that the Factory
Kawasaki Racers use. These nerfs
feature stainless steel widened and
extended race pegs with full coverage
rear nets and oversized 13/8th aluminum tubing construction. These DG
nerfs have been designed to provide
superior protection without the extra
weight and are used by both the
Kawasaki and CAN AM factory teams.
Sitting on the DRD KFX, the
improved comfort and body positioning
is instantly evident. The new foot peg
and handlebar position is noticeably
better whether you are sitting or standing. After the first few laps I couldn’t
help thinking that this was possibly one
of the fastest, easiest to ride 450’s that
I had ever ridden. The power delivery
is solid and electric like, with a hard pull
off the bottom that continues all the
way to the rev limiter. The DR.D KFX
feels like it runs; as well or better than
many other built 450’s, or even ones
with tons more money invested in big
valves, high compression pistons, and
head work. The fuel injection system
works perfectly, with super smooth
delivery that is unaffected by rough terrain, g-outs, temperature or elevation.
The DR.D Mod Box has the KFX accelerating and running like a perfectly jetted, carbureted machine with a whole
lot less jetting headache. As a further
complement to the way this Kawi
runs, all three test riders had pretty
much the same comments about the
power delivery.
The handling of the KFX is also very
impressive. Gone is the twitchy front
end, as well as any excessive body roll.
The KFX turns like it is on rails; when
you point it somewhere, that is where it
goes. The Bite MX tires hook up really
well and the front end just plain tracks.
To be truthful, the Vet track lacked a
whoop section, but it did soak up the
smaller braking bumps, coming into the
turns amazingly well. While the test
track also lacked any large double or
real technical obstacles, the KFX made
it very easy to come out of the corners
and easily get over all the tabletops, as
well soaking up flat landings when you
went a little farther than needed.
All in all, this remarkably simple build
completely changed my opinion of the
KFX450R and I would definitely consider putting one together for myself in
the near future. I was thoroughly
impressed and would recommend a
similar set up to anyone from a newbie
to a pro am MX racer. ✪
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