4 CHAMPIONS. 7 SHOOTOUTS. ZERO COMPETITIONReigning 2-straight MX and SX West Champion and winner of every major 250 shootout! More refined for 2017. The best just got even better.Features may include:Innovative Engine DesignA liquid-cooled, DOHC 4-valve, fuel-injected engine with forward-positioned downdraft intake delivers class leading engine power, updated for 2017 to further improve top-end power. This engine design allows for unmatched mass centralization, concentrating the motorcycle's key components—engine, fuel tank and exhaust system—toward the center of the motorcycle achieving light and nimble handling performance.Updated TransmissionNew gear dogs, revised gear tooth designs and a host of smaller changes create a smoother overall transmission with improved shifting, as well as a stronger overall powertrain for improved durability.
2015 Yamaha YZ250 F, 2015 Yamaha YZ250F Bike of the Year Dirt Rider s prestigious Bike of the Year and the 250 bike of choice by the majority of MX critics and experts. Standard Features May Include: 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 4-titanium-valve cylinder head is matched to a fuel injection system that provides 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 aluminum Bilateral Beam frame offers a superb rigidity balance and provides unmatched lightweight handling. 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 layout allows the silencer behind the side panel, making it closer to the middle of the bike for centralized mass for superior handling. The layout of the seat, fuel tank, air box, and wrap-around exhaust system moves the bike s mass towards the center for exceptional handling. The front intake layout with large 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. The adjustable fuel injection system uses a 44mm throttle body fed by a high-pressure battery-less electric fuel pump. This ensures optimum fuel atomization and air/fuel calibration for excellent rideability in a wide range of riding conditions. The system controls the volume of fuel injected and the ignition timing based on engine rpm and throttle opening, providing hesitation-free response and controllability. 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 unmatched handling. The large diameter 22mm front axle and top triple clamp increases rigidity for excellent handling and front end feel. The handlebar mounts are rubber mounted to improve comfort and reduce handlebar vibration. The air filter is positioned away from the rear wheel which means less maintenance for the rider.
2011 Yamaha YZ250F, 2011 Yamaha® YZ®250F Key Features May Include The Bilateral Beam frame is specific to the 250 and is more compact than the previous generation chassis. This places the rider closer to the front wheel, which delivers superb rigidity balance for unmatched lightweight handling and cornering. This nimbleness lets the rider get on the gas sooner out of corners and cross the finish line with less fatigue even on long motos. The optimized engine delivers a high level of power in the low-to- midrange, with a great torquey feel, exactly where riders want it. That is due to the straight intake boot that enhances breathing, carburetor that provides excellent throttle response and fuel atomization, and valve train components that reduce inertial mass and boost low end torque. Exhaust is also enhanced with a D-shaped exhaust port. On going refinement to the suspension and engine produces an amazingly balanced, light-handling machine with performance that's accessible to all levels of riders. The styling emphasizes the bike's light weight and nimble handling character. The sharp, horizontal lines set the bike apart with a clean, aggressive look. KYB® suspension is tuned to work with the Bilateral Beam frame for unmatched handling. The clutch lever has a light pull feel, even though the clutch has stronger engagement. The clutch also has a wide engagement range that will give riders an advantage off the line... shift after shift, moto after moto. There's no disputing the YZ250F's unmatched four-stroke prowess it was the 1st four-stroke 250 motocross bike on the market, the 1st to win an international race, the 1st to win an AMA® Supercross,® and the 1st to take an AMA® U.S. Supercross Championship® title, as well as the first to win an AMA® National race. Features & Benefits Engine The valve spring retainers are lightweight aluminum insteadof steel, and valve spring pressure is lighter for reducedvalve-opening force. This contributes to superior low-to-mid range torque characteristics due to less power-robbing friction. There's also a higher lift cam profile, while valve stem endsare 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 radiator is lower and further back and the oil tank is compactand repositioned to achieve greater mass centralization. The carburetor bore has a venturi shape, plus there's recalibrated jetting and an accelerator pump. This translates to impressive response when the rider snaps open the throttle, and contributes to superb torquey low-to-mid range power characteristics. The intake boot offers a straight, smooth tract for excellent engine breathing and more power. Th
