To keep the engine as low as
possible in the frame, the YXZ1000R’s
engine is dry sump, and the oil tank
rides above the engine behind the
passenger seat. The oil tank has
internal baffles so that it can never
starve the engine of oil on steep hills or
dune bowls. Where its competition has
paper-pleat air filters, the YXZ has two
complete air boxes and filters; the initial
filter is oiled foam like a Raptor that has
tool-less access for cleaning, and the
secondary filter is wet paper in another
airbox that sits above the engine. The
system is designed so that it can never
pass dirt into the engine, and, when the
foam filter gets too dirty, it chokes off
the engine so it stumbles and cuts out.
The intake snorkel is behind a panel
between the seats, so it draws air that’s
as clean as possible, and access to the
spin-off filter cap is under a bed-wide
cover, behind the cab, with five Dzus
fasteners.
PUTTING POWER TO THE
GROUND
For centralized mass and pure-sport
integration, the five-speed transmission
sits between the seats next to the
9-gallon fuel cell. It’s a sequential-shift
transmission (one forward, four back)
with a massive ATV-like clutch basket,
11 friction discs, 10 metal discs and 3
judder springs, plus shock dampers.
There are also dual-transmission cam
dampers on the primary and secondary
shafts, and the clutch is hydraulic, so
it never goes out of adjustment. Dustin
Nelson and others keep the throttle
pinned and stab the clutch for upshifts.
There is also an external 5.42-pound
flywheel weight to prevent stalling in
rock-crawling conditions. Yamaha
claims that the system is 15–20 percent
more efficient than a CVT and gives 10
percent more fuel efficiency. The clutch
is shared with the 1679cc V-Max street
bike.
There’s a spike-load limiter on the
outdrive, and the front differential has
another spike-load limiter with friction
and steel plates like a clutch basket.
It’s controlled by a 2WD/4WD/diff-
lock knob on the center console, and
Yamaha went to great lengths to make
the system perform flawlessly and
produce totally predictable handling.
Instead of a five-link rear-suspension
setup, the YXZ has a long lower L-arm
that transforms bump impacts from
pushing the rear tires up to more of
a rearward force. Combined with an
upper H-arm and a torsion bar, the IRS
system has the least camber change
during travel, which is 17 inches,
and the best-possible tracking. Steel
spherical bearings have rubber covers
for durability in extreme conditions.
The huge 32-inch Fox Podium 2. 5
RC2 shocks have 7/8-inch shafts and
an exclusive BOC (Bottom-Out Cup)
design; a secondary shock piston rides
above the primary piston and damping
shim stacks, and the secondary piston
is forced inside a cup at the top of
the shock near the end of travel. This
prevents bottoming and reduces loads
to the suspension and frame. The Fox
shocks also have dual-rate springs
and dual-compression adjusters,
The primary airbox rides beside the oil
tank and contains a Raptor-like oiled-foam air filter that draws air from a
panel between the seats at shoulder
level. Check out the extensive heat
shielding for the transmission inside the
center console and the sequential-shift
cables. The radiator is huge!
