• Latest-generation YZ250F-based, rear-slanting engine and bilateral beam chassis
• Forward-mounted fuel injection and wraparound exhaust
• Electric starting
• YZ-based, fully adjustable KYB suspension
• 18-inch rear wheel
• Adjustable handlebar
• GYTR Power Tuner compatible

ENGINE

• • “Reversed” liquid-cooled, 250 cc, DOHC, 4-valve (titanium), single-cylinder engine with fuel injection. The engine has been tuned for excellent rideability and controllability and delivers a broad, easy-to-use powerband with excellent power characteristics throughout the rev range. 2018 model changes improve power delivery in both low-to-mid and mid-to-top-end performance.
  • Rearward-slanted, reversed cylinder design.
    • rearward slant moves a significant amount of rotating weight toward the centre of the chassis

    rearward-slanted cylinder centralizes mass for excellent handling and a light, agile feel

  • “Reversed” engine design (FI system is front-mounted, exhaust exits from rear of cylinder).
    • forward-mounted FI provides straight intake path into the cylinder and provides optimum fuel/ air filling and flow for excellent power
    • front mounted intake design keeps fuel cooler since engine heat has less effect on incoming fuel (cooler fuel is more dense and increases power)
    • design also helps centralize mass for light, agile handling
  • Electric start with auto decompression system. Unit can be re-started in any gear.
    

NOTE: kick starter has been discontinued/removed (available as an accessory).

• • there is no main ignition switch on this model
  • electric start button (RHS handlebar) activates the entire electrical system
  • kill switch (LHS handlebar), if held for a few seconds, shuts down entire electrical system
  • removal of kick starter and related gears etc. reduces weight
• Lightweight titanium valves and revised load optimized valve springs.
  • titanium valves reduce reciprocating weight and allow for a higher rpm limit before valve float
  • titanium valves means a fast-revving engine with smooth power delivery
  • 31 mm titanium intake valves and 25 mm titanium exhaust valves
• Automatic cam chain tensioner.
  • reduces maintenance
  • special cam chain “sliders” reduce internal friction losses
• Lightweight, short-skirt, forged aluminum piston.
  • light flat-top piston features lateral ribs on both sides of the piston pin area
  • single compression ring and specially designed oil control ring increases surface contact area for optimal sealing
  • 2-ring design decreases sliding resistance, reduces weight and provides faster throttle response
• Lightweight piston pin features a diamond-like coating (DLC) to reduce friction.
• Piston oil cooler jet nozzle directs oil to the desired portion of the cylinder and underside of piston.
  • reduces piston, cylinder and rod temperatures for excellent durability
• “Liner-less” lightweight aluminum cylinder with ceramic composite coating.
  • ceramic coating sprayed directly on the aluminum block, eliminating the need for a liner and reducing weight
  • excellent heat dissipation for consistent power delivery
  • coating enhances the thin film of oil between cylinder and piston, reducing friction and increasing power
• Cylinder and crankcase “cutaways” allow air “trapped” under the piston to enter special chambers or cutaways.
  • reduces horsepower-robbing “pumping losses”
  • crankcase cutaways match cylinder cutaways for maximum efficiency
• Ball-bearing-style crankshaft.
  • bronze thrust washers located between crank webs and rod
  • heat-treated for strength and durability
  • balance ratio of the crank has been optimized for minimal vibration and good torque feeling
• Nickel-chromium-molybdenum connecting rod.
  • excellent strength and durability
• Lightweight, gear-driven counter balancer shaft.
  • reduces vibration for improved rider comfort and less rider fatigue
• 6-speed transmission utilizes a 2-bar, floating shift guide system and a 14 mm shift shaft.
• Heavy-duty, multi-plate clutch features a quick access magnesium outer cover.
  • low-friction bushing on actuation arm reduces lever pull effort
  • clutch is designed for the rigours of cross-country
  • outer cover provides fast and easy clutch access
• 44mm Keihin throttle body fuel injection system.
  • 10-hole injector
  • maximizes fuel atomization for optimal combustion and excellent power delivery
  • FI benefits include automatic adjustments to insure the optimum fuel – air ratio regardless of outside air temperature and altitude
  • other benefits include excellent starting and excellent throttle response
  • cold start knob also doubles as an idle adjuster
• Handlebar-mounted engine trouble and low fuel warning lights.
• Optional, compact, hand held “GYTR Power Tuner” allows tailoring of both fuel injection duration and ignition mapping.
  • 9 different setting points can be accessed for both fuel duration and ignition maps
  • maps can be stored and shared with other Power Tuners if desired
  • easy-access GYTR Power Tuner connector port
• Forward-mounted air box features a washable, dual-stage, foam air filter.
  • airbox cover features flush mounted quick release fasteners
  • no tools required to access air filter
  • washable foam filter reduces tune up costs
• Wet sump lubrication system.
  • reduces weight (no remote oil tank or oil lines)
  • eases maintenance (easier and faster oil changes)
  • oil volume is optimized to reduce oil related drag and weight
• Easy access “cartridge-type” oil filter.
• Compact, lightweight, single-core, YZ250F-based dual radiators.
  • outstanding cooling efficiency
  • pre-wired for accessory cooling fan—fits on right side rad only
• Maintenance-free transistor controlled ignition (TCI).
  • produces a strong spark for fast starts
  • provides precise ignition timing / mapping for optimum engine performance at all rpms
• High-capacity AC magneto eliminates need for a battery.
• Wrap-around exhaust system to match head, cam and intake.
  • exhaust exits from the rear of the engine and circles cylinder body
  • wrap-around design ensures the optimum tuned header length
  • maximizes exhaust “pulse effect” for excellent power delivery
  • centralizes mass by moving weight closer to the centre of the chassis
• Lightweight, aluminum, re-packable muffler (aka silencer).
  • sound output is 94 dB meeting AMA regulations
• Works-style, race-spec “barrel adjuster” for on-the-fly clutch lever free play adjustments.
• Heavy-duty plastic engine skid plate
• Excessive lean angle sensor
  • Will shut down the engine if the bike lays on its side
  • helps prevent costly engine damage

CHASSIS/SUSPENSION

• Compact bilateral beam aluminum frame.
  • frame design centralizes mass for exceptional handling and agility
  • frame offers an optimum balance between strength, rigidity and tuned flex, plus excellent shock absorbing qualities
  • frame design offers excellent rider-machine communication (a.k.a. feedback)
• Lightweight, tapered aluminum swingarm.
  • lightweight design reduces unsprung weight for excellent suspension performance
  • excellent rear wheel traction and control
  • large 25 mm rear axle
• Lightweight detachable rear sub frame.
  • constructed of square-section, lightweight aluminum pipe with no bends
  • allows easy access when servicing rear suspension components
• YZ250F-based, 48 mm, adjustable, inverted, Kayaba “SSS” cartridge fork offers 310 mm (12.2″) of wheel travel.
  • fork seal design features a scraper for better cleaning performance in muddy conditions
  • valving and settings are optimized for cross-country racing
  • front fork adjustments include: 20-way compression damping and 20-way rebound damping
  • optional fork springs are available through Genuine Yamaha parts.
• Fork features a twin-chamber, “Speed Sensitive System” design
  • damper unit is in a separate structure (completely separated air and oil chambers)
  • helps prevent aerated fork oil from entering the inner damper assembly and degrading its damping abilities
  • since the inner damper is pressurized; it also eliminates bubbles forming in the oil
• Fork also features a Transfer Control Valve (TCV).
  • TCV enhances damping from mid to full stroke and improves bottoming characteristics
  • TCV offers more precise control throughout the full suspension stroke
  • TCV is located on the upside of the spring and its function is controlled by piston speed, not piston position, hence the term “Speed Sensitive System fork”.
• Large “wrap-around” plastic fork protectors provide excellent lower fork tube protection.
  • “self-supporting” design reduces friction for smoother fork operation.
• YZ250F-based, Monocross link rear suspension features a fully adjustable Kayaba piggyback shock with 318 mm (12.5″) of wheel travel.
  • valving and settings are optimized for cross-country racing
  • shock features separate adjusters for high- and low-speed compression damping
  • shock adjustments include: threaded spring preload, 20-way low-speed compression damping, 2 turns of high speed compression damping and 30-way rebound damping
• Adjustable handlebar holders offer a total of 4 different handlebar positions with an adjustment range of 30mm.
  • suits wide variety of rider sizes
  • handlebar holders are rubber mounted for reduced vibration and improved rider comfort
• Large 270mm floating front “wave-style” disc and compact Nissin twin-piston caliper.
  • wave disc design reduces weight and improves cooling
  • high-friction brake pads
  • excellent braking performance
• “Shorty-style” adjustable front brake lever can be adjusted to fit various hand sizes.
• 245 mm rear disc brake uses a “wave-style” disc and single piston Nissin caliper and Nissin master cylinder.
• Rear caliper and lower portion of the disc are protected by heavy duty plastic protectors.
• Lightweight, plastic resin 7.5 litre fuel tank is located under the seat.
  • reduces centre of gravity and centralizes mass for exceptional handling performance
  • tank can be flipped on its back without disconnecting fuel line (easy servicing under the tank)
  • compact in-tank electric fuel pump
• Handlebar-mounted engine trouble and low fuel warning lights
• Compact bodywork.
  • minimizes weight and enhances the lightweight feel and look of the YZ250FX
  • flat design, “minimal” bodywork allows for fast, easy rider movements and a natural riding position
  • minimal design aids in keeping the body looking good (less plastic to scratch or damage)
  • graphics are impregnated directly into the plastic rad shrouds and will not peel off or get damaged by pressure washing
• Flat seat design.
  • provides easy rider movements
  • features a “cap cover” to access the fuel cap
  • non-slip seat cover material resists clogging with dirt or mud
• Rugged, 21″ (1.60 x 21) front and 18″ (1.85 x 18) D.I.D. rear rims.
  • excellent durability
  • reduce unsprung weight for optimal suspension performance and handling
  • 18″ rear wheel improves puncture resistance (Vs. 19″ designs)
  • Dunlop AT81 tires

DETAILS

• Convenient oil level sight glass
• Lightweight, extra wide foot pegs
• Folding shift lever tip helps prevent damage
• Lightweight chain guide / support helps reduce chance of chain derailment and helps protect rear sprocket
• Heavy duty rubber swingarm protector (chain)
• Heavy duty sealed “O” ring drive chain
• Clutch cable features integrated silicone grease and Teflon liner for smooth cable operation
• Easy access GYTR Power Tuner and Yamaha Diagnostic tool connectors
• Sealed, no spill, gel type, low maintenance battery (note: any motorcycle battery must be regularly charged during winter storage)