THE
FASTEST AMERICAN’S
ISDE MACHINE
66 www.dirtbikemagazine.com
FACTORY BIKES: INSIDE THE KTM 500 HYBRID
tolerances. The result is increased sensitivity, more fine-tuned damping, the ability to set it up stiffer yet stay plush,
and the capacity to open it up farther than a shim fork,
which helps reduce harshness.
With the Trax shock, similar manufacturing-tolerance
enhancements make for a more fine-tuned setup and
better damping. The system has a built-in design that
actually lets it ride higher over continuous hits that
normally plague a shock and cause packing. The result
is a more balanced feel, increased traction and stability
in course terrain. Also, the damping has increased
adjustability for enhanced control.
The engine started life as a 450XC-F powerplant. In
stock form, this machine is a beast and is used by the
factory KTM off-roaders in the National Hare and Hound
series. Anthony and Taylor wanted a more friendly
approach to the powerband and opted to fit it with a
500XC-W crank, which has a longer stroke. The actual
bore is identical to the 450’s (95mm), while the stroke
stretches from 63.4mm to 72mm, making it into a 510.
This completely altered the powerband, making it much
more bottom-to-mid strong with a good mix of top-end
over-rev. Compared to the 450, the 500 will short-shift
and claw for traction rather than spin and snarl. Taylor
says it lets him use the power to find traction, and it
actually relaxes the suspension and chassis—when he
rides it correctly. When he gets throttle-heavy and tries to
rev the 500, it beats him up.
One reason for the broader power of this 500 (over
a standard 500XC-W) is that the throttle body from the
XC-F line has the injectors mounted on the bottom.
This change alone makes a substantial improvement in
overall response and is one of the reasons every major
motocross team runs the KTM-type throttle body on
Taylor runs 14/48 gearing with a five-speed tranny. For the Six
Days he will run an Eco tire (lower knobs), and this he did at
the OMA race just to test it.
“Basically, it’s a 500 [XC-W] very similar to the bike that
‘Brownie’s’ riding,” Robert explains. “It’s a 500 with linkage.”
The OMA Sturgis event offered open grass-track tests and terrain that mirrors the
upcoming ISDE event in Argentina.