Yamaha just announced its dirt bikes for 2013.There are no new models or mechanical changes for the existing ones, but there are cosmetic changes for the new year.
2013 YAMAHA YZ450F
• The rearward-slanted engine allows for straight intake and
exhaust ports, creating the most direct path for airflow into the
fuel-injected engine for incredible performance.
• The YZ450F uses a battery-less fuel injection system with a
12-hole injector for superb fuel atomization. The 44mm Keihin®
throttle body is designed for easy starting, with an integrated
cold start and idle speed adjustment knob. Yamaha FI provides
optimal air/fuel mixtures in all altitudes and wide range of temperatures
for outstanding throttle response.
• Fuel injection settings (mapping for injection and advance) offer
smooth, controllable engine response in the low-to-mid-rpm
• 14 volt/110W high output generator powers the battery-less fuel
• 4-titanium valve cylinder head with a “pent-roof” design
combustion chamber provides excellent combustion efficiency
and unequalled power output.
• The big 97.0mm bore and short 60.8mm stroke, along with a high
12.5:1 compression ratio, create a combustion chamber that
delivers really impressive power.
• The air filter case is up front, helping to keep dirt and dust
kicked up from the rear tire away from the intake system.
• “Tornado-style” exhaust header with resonator efficiently scavenges
exhaust gasses and helps the engine achieve its exceptional
low-to-mid-rpm torque characteristics, while the longer
94 dB muffler meets the latest noise standards.
• Clutch and transmission components are designed to give the
rider positive and precise shifting feel.
• The aluminum double “S” bend Bilateral Beam frame is crafted
from a carefully chosen combination of forged and extruded
aluminum, 16 components in all, for the right rigidity balance
and light weight. A very symmetrical chassis design promotes
nimble handling, letting riders enter and exit corners as quickly
as possible to put the competition behind them.
• Skid plate is constructed from tough polypropylene for great
protection and low weight.
• The swingarm and rear shock are designed, with the shock
mounted along the central axis of the frame, taking advantage
of the space not needed for a traditionally configured engine’s
airbox. This optimized combination delivers exceptionally linear
performance for excellent bump absorption and awesome
• The KYB® Speed Sensitive front fork has excellent feel and
• KYB® rear shock includes a large capacity piggyback reservoir
and 50mm piston for consistent damping control.
• Front and rear suspension settings and valving deliver exceptionally
smooth suspension performance.
• Dunlop® Geomax® MX51 tires provide great all-round traction.
• Fuel tank is positioned underneath the seat, contributing to the
centralized mass. The seat is long and flat to allow free rider
movement, and has new seat foam material for an excellent
• The triple clamps have 22mm offset for unequalled cornering
performance. The tapered aluminum handlebars are 4-way
adjustable to accommodate a wide range of riders.
• The front and rear fenders, along with the number plate,
side cover and front fork protector have been designed for an
aggressive look. The bike’s minimalistic design accentuates
its handling character. A minimum of plastic means the
lightweight aluminum frame can be exposed for an enhanced
• Seat foam material has an excellent cushion feel.
2013 YAMAHA YZ250F
• The valve spring retainers are lightweight aluminum instead
of steel, and light valve spring pressure reduces valve-opening
force. Valve stem ends are chromium-nitride coated for
exceptional reliability and reduced maintenance.
• The exhaust port is “D” shaped instead of round. This increases
velocity through the port for excellent throttle response, while
enhancing the power feeling of the engine.
• The air cleaner cage design provides increased airflow, contributing
to the excellent throttle response in the mid-to-high speed
• The low-mounted radiator is as far back as possible and
the compact oil tank is positioned to achieve greater
• Larger 39mm carburetor, optimized CDI, and light piston with a
light piston pin, mean YZ250F has power as well as exceptional
throttle response in the mid-to-high speed range.
• The 39mm carburetor has a venturi-shaped bore, plus recalibrated
jetting and an accelerator pump. This translates to impressive
response when the rider snaps open the throttle, and contributes
to superb mid-to-high-rpm power characteristics.
• The intake boot offers a straight, smooth tract for excellent
engine breathing and more power. The airbox is shaped to tuck
neatly into the Bilateral Beam frame.
• The exhaust pipe has been carefully tuned to optimize engine
power, with a muffler that meets 94 dB standards.
• The Bilateral Beam frame is crafted from a carefully chosen
combination of forged and extruded aluminum pieces, all welded
together to provide unmatched rigidity balance and superb
cornering characteristics, as well as excellent handling on rough,
• The KYB® speed-sensitive front forks deliver exceptional damping
feel, responsiveness, and bump absorption characteristics.
• The 4-way-adjustable KYB® rear shock makes the most of the
latest Bilateral Beam frame design. It’s low in the frame for
excellent mass centralization, with a 16mm shaft and
settings for optimal hydraulic flow.
• The YZ250F has beefy outer fork tubes and triple clamps. The
result? The front fork assembly’s torsional rigidity for unmatched
• Fork offset is 22mm to accommodate the frame design. This
shortened offset increases trail length which, in turn, contributes
to excellent stability and reduces the inertial moment of the front
fork assembly for quick, race-winning handling. The rider can
take advantage of the higher level of performance throughout the
• The axle block portions of the swingarm provide greater rigidity
to further optimize the rigidity balance between the frame and
the revised front fork assembly.
• The tank, seat, and rear fender are flat and the relationship
between handlebars, pegs, and seat result in a natural, more
forward riding position that facilitates rider movement. The fuel
tank is placed toward the center of the bike for mass
centralization. The aluminum tapered handlebars are 4-way
adjustable, and handlebar mounts and foot pegs optimize rider
position on the chassis.
• Seat foam material has an excellent cushion feel.
• Both color options feature rich-looking black rims and a