2011 Yamaha YZ 450F

2011 Yamaha YZ450FKey Features May IncludeThe 2010 YZ450F garnered the reputable title of Dirt Rider Magazine's "Bike of the Year." Not to mention Cycle World's "Best Motocrosser" and Motorcycle Magazine’s "Best Dirtbike of 2010." YZ450F's rearward-slanted cylinder is a revolutionary advancement that achieves unmatched mass centralization, concentrating inertial mass toward the center of the machine. This bold design also swaps traditional intake and exhaust positions, putting the lightweight airbox and throttle body out front. This contributes to mass centralization for nimble handling while also achieving a straight intake tract for superb combustion efficiency that delivers more power.The cylinder is offset so the connecting rod is vertical at the moment of greatest combustion force, minimizing piston friction against the cylinder wall that could rob power. That means quicker response.The 4-titanium valve cylinder head is matched to a fuel injection system developed specifi cally for the YZ450F. Instantly adapts to changing air/fuel mixtures depending on altitude and temperature, for an engine that delivers no matter what conditions. The aluminum Bilateral Beam frame provides a superb rigidity balance that complements the engine for unmatched lightweight handling and cornering. The result? The best cornering, most nimble 450F for all track conditions.Revamped looks deliver new-generation styling, including front and rear fenders, intake cover, front fork protector, and number plate, along with the fuel tank and seat.Accessory GYTR® Power Tuner lets bike tuners adjust air/fuel mixture and ignition timing maps to match engine performance characteristics to the rider and track conditions.Features & BenefitsNew For 2011New clutch lever and pushrod for more consistent clutch feel during long motos.EngineThe rearward-slanted engine allowed engineers to design straight intake and exhaust ports, creating the most direct path for air flow into the fuel-injected engine for incredible performance.The YZ450F uses a battery-less fuel injection system with a12-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.14 volt / 110W high output generator powers the battery less fuel injection system.4-titanium valve cylinder head with a "pent-roof" design combustion chamber provides excellent combustion efficiency and unequalled power output.Intake and exhaust camshaft profile changes to increase valve working angle and valve lift for most excellent performance at all rpm.The bigger 97.0mm bore and shorter 60.8mm stroke, along with a higher 12.5:1 compression ratio, create a combustion chamber that delivers really impressive power.The air filter case is changed to accommodate the engine layout. Putting it up front keeps 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 range torque characteristics, whilethe 150mm-longer muffler comfortably meets the latest noise standards without a sacrifice of power.Clutch and transmission components have been designed to give the rider great shifting feel.