Key Features:
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- Ongoingrefinementto chassis produce an amazingly balanced, light-handlingmachine withperformance thats accessible to all levels of riders.
- Five-titanium-valve engine with 13.5:1 compression ratio spins out great torque and horsepower.
- A carefully tuned aluminum frame made up offorgings, weldings, castings and tubing means sharp, super-precise handling.
- Mass centralization provides fantastic overallbalance and performance.
- A ProTaper? aluminum handlebar in adjustable clamps and Excel rims are just a few tricks up the YZ250Fs sleeve.
- Dry sump lubrication system circulates more oil for the best durability in motocross
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New for 2009:
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- Redesignedexhaustsystem has a 60mm longer titanium header for better low-endgrunt plus a50mm shorter aluminum silencer for optimum low-rpmthrottle response.
- Bothcarburetor jettingand CDI ignition mapping settings are preciselyreworked to deliverincreased engine performance with new exhaust.
- Newclutcheliminates the judder spring and uses a floating rubber damperinsteadof a coil spring to provide unmatched clutch performance.
- Newclutcheliminates the judder spring and uses a floating rubber damperinsteadof a coil spring to provide unmatched clutch performance.
- Newly designed swingarm is lighter and helps to achieve excellent rigidity balance for superb cornering and rear wheel traction.
- Lightweight suspension linkage is redesigned to match the new swingarm.
- Newrearwheel hub is lighter and designed for the larger 25mm diameteraxle (upfrom 22mm), helping to achieve the overall rigidity balance ofrearsuspension components.
- New clutchlever is shorter, stronger,and lighter, with a lever position adjusterto accommodate differentriders. Quick adjuster makes maintenance easy.
- Front brake hose clamp is now aluminum, greatly reducing its weight.
- New seat cover has great grip and more durability, and its easy to clean.
- Premium drive chain has gold colored plates for outstanding looks.
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Engine:
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- Liquid-cooled250cc,five-titanium-valved, DOHC, four-stroke is powerful andhighlytractable, with an rpm redline for competition-crushing pullingpower.
- 37mmKeihin? FCR flat-slide carburetor with throttleposition sensor (TPS)ensures precise fuel/air mixing andlightning-quick throttle response.
- Cylinder body and crankcase feature a large cutaway section to reduce pumping loss and increase midrange performance.
- Primary kickstarting (with automatic decompression andconvenient handlebar-mounted hot start lever) ensureseasy restarts.
- Slick,five-speedtransmission with heavy-duty, multiplate clutch features aninvolutespline setup, ensuring smooth shifting and instant hookupunder power.
- Magnesium cylinder head cover - now covered matte black - helps shave weight.
- Trick, works-style clutch lever features race-spec barrel adjuster for on-the-fly adjustability.
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Chassis/Suspension:
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- Extensivelytestedaluminum frame uses a mix of alloy castings, forgings andextrusions toproduce a tuned-flex frame that makes the YZ250F thebest-handling bikein its class.
- Speed-Sensitive System 48mm KYB? fork damping force is controlled by piston speed: provides a smoother, more precise ride.
- Four-way adjustable, rear shock with Kashima-coated internals reduces friction for fantastic compliance and great handling.
- Removable aluminum rear subframe is constructed ofsquare-section tubing for light weight and easy maintenance.
- Lightweight front wheel hub for reduced unsprung weight and increased durability.
- Lightweightfrontand rear brake calipers with aluminum pistons and anti-bubblefrontmaster cylinder; wave-style rotors reduce unsprung weight anddeliverstrong stopping power.
- Lightweight 21-inch front and 19-inch rear Excel rims areexceptionally durable and reduce unsprung weight.
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