Innovative Hare Scramble/GNCC® Engine Design Based on the championship-winning YZ250F™, featuring Yamaha’s revolutionary rearward slanted, liquid-cooled, DOHC 4-stroke power plant with forward-positioned straight downdraft symmetrical intake, and with an added sixth gear and wide ratio transmission, the YZ250FX™ is an “out-of-the-box” Hare Scrambles/GNCC® competition machine
Updated Engine The all-new engine is based on the 2017 YZ250F, and includes a wide variety of updates: an all-new cylinder head, lightweight forged, two-ring, flat-top piston; a shorter, more durable piston pin with diamond like carbon (DLC) coating; a revised piston oil jet, and all-new connecting rod, crankshaft, and counterbalancer designs. Together, these updates improve peak power, power delivery and overall durability.
6-Speed Transmission A wide-ratio 6-speed transmission is used to insure the right gear is available for the wide variety of terrain found in cross-country racing.
New Chassis Nearly the same bilateral beam frame that is found on the championship winning YZ250F is used on the YZ250FX. Changes for 2017 include an all new forged section at the swingarm pivot, and revised engine mounting brackets for nimble lightweight feeling in the tight technical terrain while still providing stability in fast sections.
Advanced Suspension Industry-leading, fully adjustable KYB® spring-type fork with speed sensitive damping features revised valving for improved suspension feel and balance. The linkage type rear suspension features a KYB rear shock with updated settings optimized for cross country racing.
Cross Country Features With the electric starting system, a 2-gallon fuel tank, rugged plastic skid plate, 18-inch rear wheel and XC racing tires, the YZ250FX is ready to win right out of the box.
NEW FOR 2017
New Cylinder Head and Intake System The compact four-valve cylinder head features revised intake geometry for additional downdraft effect, matched to shorter intake funnel in the airbox, for improved top-end power. Inside the head, more aggressive camshaft profiles and valve springs boost output further, while larger valve seats ensure excellent sealing and reliability.
New Piston A new lightweight forged two-ring piston uses a flat piston crown surface with additional strengthening ribs and a shorter, more durable piston pin with diamond like carbon (DLC) coating. The new piston is lighter, significantly stronger and together with revised EFI mapping, improves combustion performance for a faster, more thorough burn, resulting in excellent pulling power.
New Crank and Connecting Rod Optimized crankshaft and counterbalancer designs feature a revised balance ratio, predictive power delivery and reduced vibration. A new nickel-chromoly steel connecting rod offers additional durability to handle the increased power output.
Stronger Crankcase The crankcase features a new heat treating process to increase strength, for protection, the frame welcomes the addition of a rugged plastic skid plate.
New 270mm Front Brake 270mm front disc (up from 250mm) brake coupled with new pad material offers outstanding braking power and performance.
Revised Suspension Systems Both front and rear dampers feature optimized settings for 2017 to further boost overall suspension performance, while the front fork utilizes a stronger oil seal system for enhanced durability in the toughest conditions.
Updated Indicators Thanks to a new WR®-style fuel level sensor in the tank, the 2017 YZ4250FX includes a convenient fuel level and engine warning indicator on the handlebar.
Unique Engine Tuning The revolutionary, rearward slanted, high-performance liquid-cooled, 4-stroke, 4-valve, fuel-injected engine has been tuned to challenge for race victories in the very competitive GNCC® and Hare Scrambles race series.
Mass-Centralized Powerplant The position of the engine moves the rotational mass of the cams towards the center of the bike which allows for a straight shot, down draft intake and straight exhaust port for maximized engine performance. Additional, this layout keeps the air box up high, out of dust and mud/water.
Fuel Injection The fuel injection system uses 3D mapped electronic control for the fuel and ignition timing that are optimized for cross-country racing.
6-Speed Gearbox A wide-ratio 6-speed transmission is used to insure the right gear is available for the wide variety of terrain found in cross-country racing.
Electric Start Push button electric start makes starting the YZ250FX easy and convenient.
Light and Strong Aluminum Frame An all-aluminum bilateral beam frame similar to the YZ250F provides strength, lightness and durability for race conditions, and for 2017 comes with a rugged plastic skid plate.
Advanced Suspension Industry favorite KYB® fully adjustable spring-type forks with speed sensitive damping and Kashima Coat™ and a KYB® rear shock, also with Kashima Coat™ and featuring a large 50mm piston. Both the fork and rear shock are tuned specifically for cross country racing, with updated fork seals for improved durability in harsh conditions.
Purpose-Built Tires Special cross-country racing Dunlop® AT81 tires are used to maximize traction while delivering excellent wear.
GYTR® Power Tuner Ready Accessory GYTR Power Tuner lets owners adjust air/fuel mixture and ignition timing maps to match engine performance characteristics to the rider and race conditions in a matter of seconds with the push of a few buttons.
Practical Touches Quick-adjust clutch, wide 55mm platform footpegs, four-position rubber- mounted handlebar clamps, aluminum handlebars, and a side stand are standard for added rider convenience. The YZ250FX is also pre-wired for an optional radiator fan for the most grueling conditions.
Easy Servicing Redesigned air cleaner cover helps prevent contact with the quick-release quarter-turn Dzus® air box fasteners for tool-less access to the air filter.
Sealed O-ring Chain High-quality O-ring chain is tough and durable.