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Description
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Conquer Dirt
We've taken our revolutionary YZ four stroke motocross technology and applied it to the enduro world. Rearward slanted engine, reversed cylinder, forward mounted fuel injection and a compact chassis are just some of the key features found on the WR250F. Delivering light, agile handling on tight trails, the WR is also a great choice for the experienced recreational rider too.
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/// Performance
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 The latest generation YZ250F engine is the inspiration for the WR power plant. A forward mounted 44 mm fuel injection system supplies fuel to the 4-valve cylinder head, while the wrap around exhaust removes the spent charge and centralizes mass at the same time. A couple of items you won't find on a YZ250F is the WR's 6-speed transmission, electric starting and radiator cooling fan. |
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/// Frame & Suspension
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 The adjustable KYB suspension found on our YZs is considered by many to be the best in the biz. So, we have added them as well as our Bilateral Beam all aluminum frame to the WR. Adjustable KYB "SSS" forks and piggyback rear shock allow you to tailor suspension settings to match weight, riding style and terrain. While the chassis design centralizes mass for fast, accurate, agile handling. |
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/// Key Features
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Latest generation YZ250F based rear slanting engine & Bilateral Beam chassis
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Forward mounted fuel injection & mass centralizing wrap around exhaust
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Electric starting
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6-speed transmission
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YZ based, adjustable suspension
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18 inch rear wheel
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Rad fan
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Adjustable handlebar
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35 watt headlight & LED tail light
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GYTR Power Tuner compatible (Competition Only Kit ECU is required)
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/// ENGINE
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YZ250F based, "reversed" liquid-cooled, 250cc, DOHC, 4-valve (titanium), 4-stroke, single with fuel injection & electric starting. The engine has been tuned for excellent "ride ability & controllability" and delivers a broad, easy to use power band with excellent power characteristics for enduro style racing or riding.
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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 & a light feel
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"Reversed" engine design (FI system is front mounted, exhaust exits from rear of cylinder).
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FI throttle body & air box are front mounted, providing a straight intake path
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straight intake path into the cylinder, provides optimum fuel / air 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 & increases power)
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design also helps centralize mass for light, agile handling
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Electric start with manual kick starter & auto decompression system. Unit can be re-started in any gear.
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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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design reduces weight
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Compact 4-valve cylinder head features a 13.5:1 compression ratio.
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titanium 31 mm intake valves & titanium 25 mm exhaust valves
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23.75 degree valve angle provides a compact combustion chamber
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4-valve design offers optimum flow & excellent power characteristics
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Lightweight titanium valves with load-reduced, oval valve springs.
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reduces reciprocating weight & allows for a higher rpm limit
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reduced friction (load reduced valve springs)
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faster-revving & smoother power delivery
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Automatic cam chain tensioner.
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reduces maintenance
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special cam chain "sliders" reduce internal frictional losses
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Lightweight hollow intake & exhaust camshafts.
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provide a broad power band well suited to enduro style racing or riding
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Lightweight aluminum cylinder features a ceramic composite coating applied directly to the aluminum block.
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ceramic coating sprayed directly on the aluminum block, eliminating the liner & 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 the cylinder & piston, reducing friction & increasing power
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Special cylinder "cutaways" allow air "trapped" under the piston to enter a side chamber (or cutaway) to reduce horsepower-robbing "pumping losses."
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The crankcase also utilizes cutaways to reduce "pumping losses". The crankcase cutaways match the cutaways in the cylinder for maximum efficiency.
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Lightweight, short-skirt, forged aluminum piston uses a 2-ring design.
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single compression ring & a specially designed oil control ring that increases the surface contact area for better sealing
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2-ring design decreases sliding resistance, reduces weight & provides faster throttle response
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Piston oil cooler jet nozzle directs oil to the desired portion of the cylinder & underside of piston.
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reduces piston, cylinder & rod temperatures for excellent durability
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Crankcase features a tri-axis layout for the crank, main & drive axles.
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tri-axis design means lighter, more compact crankcases
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centralizes mass for excellent handling
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reduces the centre of gravity for a lighter feeling
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Lightweight YZ250F inspired crankshaft & connecting rod features a carburizing process for excellent durability.
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Lightweight gear driven counter balancer shaft.
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reduces vibration for improved rider comfort & less rider fatigue
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6-speed transmission utilizes a 2-bar, floating shift guide system & a 14 mm shift shaft.
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smooth, positive shifts
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good durability in the event of a crash (14 mm shift shaft)
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Heavy duty, multi-plate, clutch with quick access magnesium outer cover.
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clutch is designed for the rigours of enduro racing / riding
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clutch action is light to reduce hand fatigue during extended events / rides
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outer cover provides fast & easy clutch access
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44mm Keihin throttle body fuel injection system.
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10-hole injector with a 16 degree spray pattern
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maximizes fuel atomization for more complete combustion & excellent power delivery
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FI settings are specific to enduro type racing / riding
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FI benefits include automatic adjustments to insure the optimum fuel - air ratio regardless of outside air temperature & altitude
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other benefits include excellent starting & excellent throttle response
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cold start knob also doubles as an idle adjuster
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The injector spray pattern, spray direction & distance to the intake valves have been optimized. Forward mounted straight intake tract helps to maximize the benefits of the FI system & overall power output.
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Optional, compact, hand held "GYTR Power Tuner" allows tailoring of both fuel injection duration & ignition mapping.
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9- different setting points can be accessed for both fuel duration & ignition maps
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maps can be stored & shared with other Power Tuners if desired
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NOTE: Competition Only Kit ECU is required for Power Tuner use
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Forward mounted air box features a washable, dual-stage, foam air filter.
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No tools required to access air filter
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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 & faster oil changes)
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Easy access "cartridge-type" oil filter.
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Lightweight, single core, dual rads with electric cooling fan.
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standard cooling fan maintains consistent engine temperatures during slow speed, technical riding
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radiator fin pitch is optimized for good air flow even at slow speeds
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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 (160 watts @ 5,000 rpm).
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Lightweight, wrap-around exhaust system based on YZ250F design.
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exits from the rear of the engine & circles cylinder body
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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 / stainless steel muffler (aka silencer).
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multi-expansion design
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spark arrestor equipped
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/// CHASSIS/SUSPENSION
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YZ250F based, compact, lightweight "Bilateral Beam" aluminum frame.
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centralizes mass for exceptional handling & maneuverability in tight terrain
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frame offers an optimum rigidity balance between strength, rigidity & 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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reduces unsprung weight for excellent suspension performance
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excellent rear wheel traction & control
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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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48mm, adjustable, inverted, Kayaba "SSS" cartridge fork offers 310mm (12.2") of wheel travel.
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valving & settings are designed for enduro racing / riding
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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 meaning the damper unit is in a separate structure (completely separated air & oil chambers) which prevents aerated fork oil from entering the inner damper assembly & degrading its damping abilities. 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 & 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 & 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.
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provide excellent lower fork tube protection
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"self-supporting" design reduces friction for smoother fork operation.
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Monocross link rear suspension features a fully adjustable Kayaba piggyback shock with 318 mm (12.5") of wheel travel.
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features separate adjusters for high- and low-speed compression damping
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shock is in-line with the center axis of the frame for excellent control
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shock valving & settings are tailored for enduro riding
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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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250mm floating front "wave-style" disc & compact Nissin twin piston caliper.
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wave disc design reduces weight & improves cooling
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"Shorty style" adjustable front brake lever can be adjusted to fit various hand sizes.
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245mm rear disc brake features a "wave-style" disc & a single piston Nissin caliper & master cylinder.
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Rear caliper & lower portion of the wave style disc are protected by heavy duty plastic protectors.
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Lightweight, plastic resin 7.5 litre fuel tank with compact in-tank electric fuel pump, is located under the seat.
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reduces centre of gravity & 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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2.0 litre reserve portion ( low fuel light will illuminate)
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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 & improved rider comfort.
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Compact body work.
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reduces weight & enhances the lightweight feel & look of the WR250F
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flat design, "minimal" bodywork allows for fast, easy rider movements & 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 & 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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Lightweight digital meter assembly.
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functions include: speedometer, odometer, dual trip meters & clock in the basic mode
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"race mode" features pace management functions including; timer & distance compensating trip meter
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warning lights for engine trouble (FI system) & low fuel
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Rugged, 21" (1.60 x 21) front & 18" (2.15 x 18) rear D.I.D. rims.
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excellent durability
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reduces unsprung weight for optimal suspension performance & handling
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18" rear wheel improves puncture resistance (Vs. 19" designs)
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Dunlop MX51 series.
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Stylish, slim design 35 watt headlight.
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headlight beam is adjustable up & down
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Brilliant LED rear taillight.
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/// Details
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Rugged plastic engine skid plate
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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
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Lightweight chain guide / support helps reduce chance of chain derailment & 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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Easy access GYTR Power Tuner & Yamaha Diagnostic tool connectors
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Sealed, no spill, gel type, low maintenance battery (battery should be charged during winter storage)
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