450 OFF-ROAD SHOOTOUT
True off-road credentials
Of these four makers, Yamaha put the most effort into
making a legitimate off-road bike. The YZ450FX has a long
list of part numbers to prove it’s not the same bike as the
YZ450F motocross bike. Most of those are in the gearbox.
It has a true wide-ratio transmission with a granny first
gear. Like all the others, it has softer suspension than the
MX bike, an 18-inch rear wheel and a kickstand. Like the
Honda, it got an electric starter to complete the transformation. For 2017 Yamaha removed the kick-start lever
to save a little weight. It doesn’t have handguards, but it
does have a skid plate. The only item that the Yamaha
lacks, compared to the others, is a larger fuel tank. It has
the same tank as the MX bike, but at least it’s a large MX
tank that holds 2 gallons. As on the MX bike, the tank is
located under the seat and the airbox is up top. It also
has Yamaha’s signature rearward-tilted top end with the
exhaust in the rear.
ON THE TRACK
The Yamaha has the hardest-hitting powerband. This
might not show on the dyno charts, but the fact remains
that the YZ450FX is a very powerful machine. If you have
a wide-open track with steep, soft hills, it’s difficult not to
smile. The bike will go as fast and as hard as you ask it
to. The bike’s designers didn’t give it a map switch, but
Yamaha does offer the handheld GYTR Power Tuner,
which allows you to tailor the power output as you please.
The standard map is milder than that of the MX bike but
still very aggressive. The off-road gearbox doesn’t help
much on the MX sections of a GP course. In fact, you have
to be careful not to click it into first by accident—that’s like
throwing out a parachute! Suspension-wise, the Yamaha
has long been outstanding. The KYB fork and shock are
a little softer than those of the YZ450F and work well for
just about everyone. Pros might complain that the bike is
too soft for big jumps and high speeds, and that’s where
you pay the price for having coil-spring forks. You can’t
just add a few pounds of pressure. Still, most riders say
the Yamaha fork is their favorite of this group, even if they
might have to modify it for a specific application.
ON THE TRAIL
The YZ450FX’s gearbox generated much heated debate
among DB test riders. The bottom line is that if you’re
trying to maintain a good pace, you don’t use first gear
very often, even on tight trails. It’s more of a just-in-case
feature. Second gear, which is a little taller than first on the
others, is where you’ll spend most of your time. If you’re
a desert racer, the gearbox can be a big advantage. You
can re-gear the bike for 90 mph and still handle tight, slow
trails with ease. And, if you’re a casual trail rider, you’ll use
first frequently and never worry about stalling. The problem
is that the aggressive power delivery is even harder to deal
with in such a low gear. The Yamaha’s clutch is excellent,
and even when you abuse it, the bike rarely overheats.
The real issue with the Yamaha on the trail is the weight.
It’s the heaviest at 251 pounds without fuel, and doesn’t
disguise that fact well. It’s a big, heavy, fast bike, and that
doesn’t usually mix well with technical trails.
Yamaha doesn’t have to make the YZ450FX into a fluffy
trail bike, because the company offers the WR450F. That’s
the same motorcycle but with official off-road certification
and a much milder personality. Offering the WR leaves
Yamaha free to make the YZ450FX a bit of a fire-breather.
The best part about the FX is that Yamaha did the hard
work. Anyone can tune a motor, re-valve suspension or
bolt on an aftermarket fuel tank, but only a manufacturer
can design a wide-ratio gearbox.