New liquid-cooled, DOHC 4-valve, fuel-injected
engine with the same forward-positioned, straight
intake, rear-inclined cylinder, and rear-positioned
exhaust layout as the YZ450F. This new engine has
more power than the ’13 YZ250F, especially in the
mid-to-high rpm range.
The 4-titanium-valve cylinder head is matched to
a new fuel injection system that provides more
power at mid-to-high rpm. The fuel injection system
instantly adjusts the air/fuel mixtures depending
on altitude and temperature, for a hesitation-free
engine that delivers no matter the conditions.
The new aluminum Bilateral Beam frame offers
a superb rigidity balance and, with new front and
rear suspension components and settings, provides
unmatched lightweight handling. Even fans of the
previous YZ250F will be sure to notice the solid
handling characteristics, including the light feel in
tight corners and during direction changes.
The exhaust pipe has an innovative layout, circling
the cylinder, giving the exhaust pipe proper length
for an excellent exhaust pulse effect. At the same
time, the exhaust pipe has three different diameters
throughout the exhaust tract, bringing out excellent
power characteristics. This new layout allows the
silencer to be positioned 190mm further forward, behind
the side panel, making it closer to the middle of
the bike for centralized mass for superior handling.
The all-new layout of the seat, fuel tank, air box, and
wrap-around exhaust system moves the bike’s mass
towards the center for exceptional handling. And, in
addition to an all-new appearance, the front intake
layout with larger air filter element adds the benefit
of reduced air filter maintenance due to its positioning
away from dirt roost from the rear wheel.
Accessory GYTR® Power Tuner lets owners adjust
air/fuel mixture and ignition timing maps to match
engine performance characteristics to the rider and
track conditions in a matter of seconds with the
push of a few buttons.
A new liquid-cooled, DOHC 4-valve, fuel-injected engine with the
same forward-positioned straight intake, rear-inclined cylinder
and rear-positioned exhaust layout as the YZ450F. The new
engine, with its straight and symmetrical intake and exhaust
ports and compact, high-compression combustion chamber,
delivers outstanding engine character with more power output
and deeper power in the high-speed range.
The new, adjustable fuel injection system uses a 44mm throttle
body fed by a high-pressure battery-less electric pump to ensure
optimum fuel atomization and air/fuel calibration for excellent
readability in a wide range of riding conditions The system
provides 3-dimensionally mapped control of the volume of fuel
injected and the ignition timing based on engine rpm and throttle
opening. This ensures hesitation-free response and controllability
and contributes to the high level of high-rpm power.
Various detailed design measures are adopted to reduce horsepower
loss. The forged 2-ring piston is light weight and is cooled
by an oil spray jet. In addition, the compression ring is a singlering
design instead of the conventional two ring. This new piston
and rings, along with the offset cylinder configuration reduce
friction loss and contribute to quicker response. What’s more,
the new specs for the intake/exhaust ports, new cam profiles,
new ECU, new carburized crank, optimized balance ratios for
the crank web, the newly designed transmission, strengthened
clutch design, and other features, all work together to create the
YZ250F’s outstanding engine character with more power output
and deeper power in the high-rpm range.
As with the YZ450F, an innovative exhaust pipe design is adopted
to increase mass centralization and improve power development
characteristics. This layout moves the rear end of the exhaust
pipe farther forward and enables a muffler position that is closer
to the machine’s center of gravity. Adjustments are made in
the pipe diameter in its various sections resulting in excellent
exhaust pulse effect that contributes to stronger high rpm power
The compact wet sump lubrication system with piston cooler
spray jet maintains excellent engine durability and eliminates the
need for an oil tank, which lowers engine weight. This creates a
more compact engine that contributes to mass centralization and
Newly designed transmission and shift mechanisms reduce
drive-force loss during gear changes and produce smoother shift
operations and surer shift action.
A newly designed aluminum Bilateral Beam frame is adopted. The
overall dimensions are roughly the same as the frame of the 2013
model YZ250F. This gives the new YZ250F a compact chassis that
provides a lightweight feeling while leaned over and in the air
while also providing solid handling and bump stability.
The aluminum muffler is positioned closer to the machine’s center
of gravity as it is almost completely hidden by the side number
plate. The layout allows a shorter, lighter rear sub frame and
also contributes to centralized mass for a lightweight handling
The front suspension has proven KYB® air-oil separated forks. It
adopts new spec inner and outer tubes coupled with optimized
suspension settings. The new rear suspension also features a
new reservoir location and spring spec with settings optimized
for ideal damping characteristics to match the new chassis
The new larger diameter 22mm front axle and new top triple
clamp increases rigidity for improved handling and front end
feel. The handlebar mounts are now rubber mounted to improve
comfort and reduce handlebar vibration.
The air filter is now positioned away from the rear wheel which
means less maintenance for the rider.
“In-mold graphics” technology is a method in which the graphics
are molded into the radiator shrouds for improved decal durability
and reduced scratches.
Riders have a choice of two color options: Team Yamaha Blue/
White or White/Red.