Description
Conquer Dirt
The high-flying, high-paced action of motocross is not for everyone. As a result, the slightly less intense world of cross country / hare scramble racing is a popular alternative. The YZ250FX is a cross-country-focused model with the performance potential of the YZ250F. If you are serious about winning, the YZ250FX could be the machine for you.
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PERFORMANCE
The YZ250FX uses the reversed-cylinder, rearward-slanted engine from the previous-gen YZ250F with modified fuel injection settings, electric start and a 6-speed transmission. |
The Extras
Featuring a KYB speed-sensitive fork and fully adjustable KYB rear shock, the FX uses the same suspension as its MX cousin with softer settings and slightly more rear wheel travel. Also included is a lightweight aluminum side stand, adjustable handlebar and an 18-inch rear wheel. .
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Features & Benefits
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Key features for 2019
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Latest-generation YZ250F-based, rear-slanting engine and bilateral beam chassis
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Forward-mounted fuel injection and wraparound exhaust
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Electric starting
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YZ-based, fully adjustable KYB suspension
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18-inch rear wheel
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Adjustable handlebar
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GYTR Power Tuner compatible
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ENGINE
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"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.
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Rearward-slanted, reversed cylinder design.
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rearward slant moves a significant amount of rotating weight toward the centre of the chassis
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rearward-slanted cylinder centralizes mass for excellent handling and a light, agile feel
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"Reversed" engine design (FI system is front-mounted, exhaust exits from rear of cylinder).
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forward-mounted FI provides straight intake path into the cylinder and provides optimum fuel/ air filling and flow for excellent power
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front mounted intake design keeps fuel cooler since engine heat has less effect on incoming fuel (cooler fuel is more dense and increases power)
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design also helps centralize mass for light, agile handling
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Electric start with auto decompression system. Unit can be re-started in any gear.
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NOTE: kick starter has been discontinued/removed (available as an accessory).
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there is no main ignition switch on this model
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electric start button (RHS handlebar) activates the entire electrical system
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kill switch (LHS handlebar), if held for a few seconds, shuts down entire electrical system
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removal of kick starter and related gears etc. reduces weight
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Lightweight titanium valves and revised load optimized valve springs.
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titanium valves reduce reciprocating weight and allow for a higher rpm limit before valve float
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titanium valves means a fast-revving engine with smooth power delivery
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31 mm titanium intake valves and 25 mm titanium exhaust valves
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Automatic cam chain tensioner.
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reduces maintenance
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special cam chain "sliders" reduce internal friction losses
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Lightweight, short-skirt, forged aluminum piston.
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light flat-top piston features lateral ribs on both sides of the piston pin area
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single compression ring and specially designed oil control ring increases surface contact area for optimal sealing
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2-ring design decreases sliding resistance, reduces weight and provides faster throttle response
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Lightweight piston pin features a diamond-like coating (DLC) to reduce friction.
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Piston oil cooler jet nozzle directs oil to the desired portion of the cylinder and underside of piston.
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reduces piston, cylinder and rod temperatures for excellent durability
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"Liner-less" lightweight aluminum cylinder with ceramic composite coating.
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ceramic coating sprayed directly on the aluminum block, eliminating the need for a liner and reducing weight
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excellent heat dissipation for consistent power delivery
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coating enhances the thin film of oil between cylinder and piston, reducing friction and increasing power
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Cylinder and crankcase "cutaways" allow air "trapped" under the piston to enter special chambers or cutaways.
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reduces horsepower-robbing "pumping losses"
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crankcase cutaways match cylinder cutaways for maximum efficiency
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Ball-bearing-style crankshaft.
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bronze thrust washers located between crank webs and rod
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heat-treated for strength and durability
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balance ratio of the crank has been optimized for minimal vibration and good torque feeling
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Nickel-chromium-molybdenum connecting rod.
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excellent strength and durability
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Lightweight, gear-driven counter balancer shaft.
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reduces vibration for improved rider comfort and less rider fatigue
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6-speed transmission utilizes a 2-bar, floating shift guide system and a 14 mm shift shaft.
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Heavy-duty, multi-plate clutch features a quick access magnesium outer cover.
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low-friction bushing on actuation arm reduces lever pull effort
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clutch is designed for the rigours of cross-country
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outer cover provides fast and easy clutch access
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44mm Keihin throttle body fuel injection system.
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10-hole injector
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maximizes fuel atomization for optimal combustion and excellent power delivery
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FI benefits include automatic adjustments to insure the optimum fuel - air ratio regardless of outside air temperature and altitude
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other benefits include excellent starting and excellent throttle response
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cold start knob also doubles as an idle adjuster
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Handlebar-mounted engine trouble and low fuel warning lights.
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Optional, compact, hand held "GYTR Power Tuner" allows tailoring of both fuel injection duration and ignition mapping.
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9 different setting points can be accessed for both fuel duration and ignition maps
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maps can be stored and shared with other Power Tuners if desired
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easy-access GYTR Power Tuner connector port
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Forward-mounted air box features a washable, dual-stage, foam air filter.
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airbox cover features flush mounted quick release fasteners
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no tools required to access air filter
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washable foam filter reduces tune up costs
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Wet sump lubrication system.
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reduces weight (no remote oil tank or oil lines)
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eases maintenance (easier and faster oil changes)
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oil volume is optimized to reduce oil related drag and weight
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Easy access "cartridge-type" oil filter.
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Compact, lightweight, single-core, YZ250F-based dual radiators.
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outstanding cooling efficiency
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pre-wired for accessory cooling fan—fits on right side rad only
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Maintenance-free transistor controlled ignition (TCI).
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produces a strong spark for fast starts
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provides precise ignition timing / mapping for optimum engine performance at all rpms
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High-capacity AC magneto eliminates need for a battery.
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Wrap-around exhaust system to match head, cam and intake.
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exhaust exits from the rear of the engine and circles cylinder body
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wrap-around design ensures the optimum tuned header length
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maximizes exhaust "pulse effect" for excellent power delivery
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centralizes mass by moving weight closer to the centre of the chassis
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Lightweight, aluminum, re-packable muffler (aka silencer).
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sound output is 94 dB meeting AMA regulations
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Works-style, race-spec "barrel adjuster" for on-the-fly clutch lever free play adjustments.
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Heavy-duty plastic engine skid plate
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Excessive lean angle sensor
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Will shut down the engine if the bike lays on its side
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helps prevent costly engine damage
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CHASSIS/SUSPENSION
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Compact bilateral beam aluminum frame.
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frame design centralizes mass for exceptional handling and agility
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frame offers an optimum balance between strength, rigidity and tuned flex, plus excellent shock absorbing qualities
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frame design offers excellent rider-machine communication (a.k.a. feedback)
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Lightweight, tapered aluminum swingarm.
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lightweight design reduces unsprung weight for excellent suspension performance
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excellent rear wheel traction and control
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large 25 mm rear axle
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Lightweight detachable rear sub frame.
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constructed of square-section, lightweight aluminum pipe with no bends
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allows easy access when servicing rear suspension components
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YZ250F-based, 48 mm, adjustable, inverted, Kayaba "SSS" cartridge fork offers 310 mm (12.2") of wheel travel.
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fork seal design features a scraper for better cleaning performance in muddy conditions
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valving and settings are optimized for cross-country racing
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front fork adjustments include: 20-way compression damping and 20-way rebound damping
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optional fork springs are available through Genuine Yamaha parts.
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Fork features a twin-chamber, "Speed Sensitive System" design
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damper unit is in a separate structure (completely separated air and oil chambers)
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helps prevent aerated fork oil from entering the inner damper assembly and degrading its damping abilities
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since the inner damper is pressurized; it also eliminates bubbles forming in the oil
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Fork also features a Transfer Control Valve (TCV).
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TCV enhances damping from mid to full stroke and improves bottoming characteristics
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TCV offers more precise control throughout the full suspension stroke
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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".
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Large "wrap-around" plastic fork protectors provide excellent lower fork tube protection.
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"self-supporting" design reduces friction for smoother fork operation.
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YZ250F-based, Monocross link rear suspension features a fully adjustable Kayaba piggyback shock with 318 mm (12.5") of wheel travel.
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valving and settings are optimized for cross-country racing
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shock features separate adjusters for high- and low-speed compression damping
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shock adjustments include: threaded spring preload, 20-way low-speed compression damping, 2 turns of high speed compression damping and 30-way rebound damping
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Adjustable handlebar holders offer a total of 4 different handlebar positions with an adjustment range of 30mm.
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suits wide variety of rider sizes
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handlebar holders are rubber mounted for reduced vibration and improved rider comfort
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Large 270mm floating front "wave-style" disc and compact Nissin twin-piston caliper.
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wave disc design reduces weight and improves cooling
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high-friction brake pads
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excellent braking performance
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"Shorty-style" adjustable front brake lever can be adjusted to fit various hand sizes.
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245 mm rear disc brake uses a "wave-style" disc and single piston Nissin caliper and Nissin master cylinder.
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Rear caliper and lower portion of the disc are protected by heavy duty plastic protectors.
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Lightweight, plastic resin 7.5 litre fuel tank is located under the seat.
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reduces centre of gravity and centralizes mass for exceptional handling performance
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tank can be flipped on its back without disconnecting fuel line (easy servicing under the tank)
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compact in-tank electric fuel pump
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Handlebar-mounted engine trouble and low fuel warning lights
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Compact bodywork.
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minimizes weight and enhances the lightweight feel and look of the YZ250FX
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flat design, "minimal" bodywork allows for fast, easy rider movements and a natural riding position
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minimal design aids in keeping the body looking good (less plastic to scratch or damage)
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graphics are impregnated directly into the plastic rad shrouds and will not peel off or get damaged by pressure washing
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Flat seat design.
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provides easy rider movements
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features a "cap cover" to access the fuel cap
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non-slip seat cover material resists clogging with dirt or mud
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Rugged, 21" (1.60 x 21) front and 18" (1.85 x 18) D.I.D. rear rims.
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excellent durability
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reduce unsprung weight for optimal suspension performance and handling
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18" rear wheel improves puncture resistance (Vs. 19" designs)
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Dunlop AT81 tires
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Convenient oil level sight glass
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Lightweight, extra wide foot pegs
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Folding shift lever tip helps prevent damage
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Lightweight chain guide / support helps reduce chance of chain derailment and helps protect rear sprocket
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Heavy duty rubber swingarm protector (chain)
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Heavy duty sealed "O" ring drive chain
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Clutch cable features integrated silicone grease and Teflon liner for smooth cable operation
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Easy access GYTR Power Tuner and Yamaha Diagnostic tool connectors
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Sealed, no spill, gel type, low maintenance battery (note: any motorcycle battery must be regularly charged during winter storage)
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