We admit that a
250cc four-stroke isn’t
the right bike if you’re
aiming for the
overall win. We
in those terms.
A top five and
perhaps a class
for a small-bore
WR can do that
and beat its share of
larger-displacement bikes along the way,
because it can easily be made to produce as
much power as the YZ version, and it has a
wide-ratio gearbox for those long stretches
of open Nevada desert. Also, the mass starts
that favored big bikes are long gone. Vegas to Reno and
virtually all long-distance races are timed nowadays.
The first part of the WR’s conversion is easy. Yamaha’s
accessory division sells a power-up kit that has a different
CPU for the ignition and a new throttle stop. Remember,
the WR250F is sold as an off-road model that meets EPA
and CARB emission requirements. In stock form, the
throttle doesn’t open all the way. To finish the competition conversion, you need an exhaust like the FMF F4.1
Ti system. Even with the accessory
black box the WR still doesn’t quite run like a YZ, unless
you do a little remapping using the Yamaha Power Tuner.
If you have time to do your own testing, it’s not a difficult
process; you can simply add fuel and advance the spark
until it feels faster. In this case, we used a more efficient
method. We installed a Dynojet Power Commander with
settings worked out by Jett Tuning. The motor was geared
up slightly with a 14/48 sprocket combination. The WR still
has a decently low first gear, but Vegas to Reno also has
its share of technical sections, so we installed a Rekluse
Core EXP 3.0 automatic clutch just to help eliminate the
possibility of stalling. We still had the WR’s electric starter;
we don’t understand why anyone would disable that for
the scant weight savings. In fact, you need a battery and a
headlight for this race anyway.
The winning bike usually finishes in the mid-afternoon,
but, by definition, the winning bike has no trouble en route.
Anything can happen in 500 miles, and as much as half
the motorcycle field has been known to finish after dark.
So, the battery has to stay in place to power the headlight.
Luckily, getting good light out of the WR is easy. The stock
headlight isn’t worth much, but the Baja Designs Squadron
Pro is a compact headlight that doesn’t require any more
space than the stocker and produces about 10 times the
light using four small LED lamps in a Polysport plastic
frame. It costs about $250 but bolts on to the WR without
any stator work or anything. We used an EarthX lithium- Warp 9 wheels were set up for Vegas to Reno, while the stockers were saved as spares.
ZLT and UFO made the
Yamaha look sweet.
YAMAHA WR250F MODS