Key Features:

• Ongoing refinement to chassis produce an amazingly balanced, light-handling machine with performance that’s accessible to all levels of riders.
• Five-titanium-valve engine with increased compression spins out even more torque and horsepower.
• A carefully tuned aluminum frame made up of forgings, weldings, castings and tubing means sharp, super-precise handling.
• Mass centralization provides fantastic overall balance 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

New for 2009:

• Redesigned exhaust system has a 60mm longer titanium header for better low-end grunt plus a 50mm shorter aluminum silencer for optimum low-rpm throttle response.
• Both carburetor jetting and CDI ignition mapping settings are precisely reworked to deliver increased engine performance with new exhaust.
• New clutch eliminates the judder spring and uses a floating rubber damper instead of a coil spring to provide unmatched clutch performance.
• New clutch eliminates the judder spring and uses a floating rubber damper instead of 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.
• New rear wheel hub is lighter and designed for the larger 25mm diameter axle (up from 22mm), helping to achieve the overall rigidity balance of rear suspension components.
• New axle blocks make chain adjustment a cinch.
• New clutch lever is shorter, stronger, and lighter, with a lever position adjuster to accommodate different riders. 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.

Engine:

• Liquid-cooled 250cc, five-titanium-valved, DOHC, four-stroke is powerful and highly tractable, with an rpm redline for competition-crushing pulling power.
• 37mm Keihin FCR flat-slide carburetor with throttle position sensor (TPS) ensures precise fuel/air mixing and lightning-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 and convenient handlebar-mounted hot start lever) ensures easy restarts.
• Slick, five-speed transmission with heavy-duty, multiplate clutch features an involute spline setup, ensuring smooth shifting and instant hookup under 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.

Chassis/Suspension:

• Extensively tested aluminum frame uses a mix of alloy castings, forgings and extrusions to produce a tuned-flex frame that makes the YZ250F the best-handling bike in 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 of square-section tubing for light weight and easy maintenance.
• Lightweight front wheel hub for reduced unsprung weight and increased durability.
• Lightweight front and rear brake calipers with aluminum pistons and anti-bubble front master cylinder; wave-style rotors reduce unsprung weight and deliver strong stopping power.
• Lightweight 21-inch front and 19-inch rear Excel rims are exceptionally durable and reduce unsprung weight.