Engine

Powering the new WR450F is the latest reverse-fed, mass-centralized 449 cc single from the current YZ450F, but with specific enduro settings. Layout and specifications are the same as the YZ450F engine, but the intake and exhaust systems, fuel injection and ignition advance maps are tuned to provide the fast enduro rider with stronger and longer-lasting pulling power at high rpm.

Handling

Using The Same Bilateral Beam Frame And Proven Kyb Suspension As The Current Yz450f, The Wr450f Has Been Tuned For The Enduro Environment. The Result Is Excellent Stability, Feedback, Response And Light Handling.

Key Features

 

• Engine based on latest-generation YZ450F motocross bike

• "Reversed" rearward-slanted engine design with 4-valve cylinder head (titanium valves)
• Forward-mounted fuel injection & rear-exiting wraparound exhaust
• Electric starting
• 5-speed, wide ratio transmission
• Radiator fan
• Bilateral Beam aluminum frame
• YZ based, fully adjustable suspension
• 18-inch rear wheel
• 35-watt headlight & LED tail light
• Power Tuner app compatible (Competition-Only Kit CCU is required)

Engine

YZ450F-based, "reversed" liquid-cooled, 450 cc, DOHC, 4-valve (titanium), 4-stroke, single with fuel injection & electric starting.

• engine has been tuned for excellent rideability & control
• broad, easy-to-use powerband
• power characteristics optimized for enduro style racing or riding

Rearward-slanted, reversed cylinder design.

• rearward slant moves a significant amount of rotating weight toward the centre of the chassis
• rearward-slanted design centralizes mass for excellent handling & a light feel

"Reversed" engine design - FI system is front-mounted, exhaust exits from rear of cylinder.

• FI throttle body & air box are front-mounted, providing a straight intake path
• straight intake path into the cylinder provides optimum fuel/ air flow for excellent power
• front-mounted intake keeps fuel cooler since engine heat has less effect on incoming fuel (cooler fuel is more dense & increases power)
• design centralizes mass for light, agile handling

Electric start with auto decompression system.

• unit can be re-started in any gear
• elimination of kick starter reduces weight

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
• design reduces weight

Compact 4-valve cylinder head features a 12.8:1 compression ratio.

• titanium 37 mm intake valves & titanium 30.5 mm exhaust valves - TBD
• 4-valve design offers optimum flow for excellent power & torque
• compact combustion chamber design

Lightweight titanium valves use load-reduced valve springs.

• titanium valves reduce reciprocating weight & allow for a higher rpm limit (40% lighter than steel valves)
• reduced friction (load reduced valve springs)
• faster-revving & smoother power delivery

Automatic cam chain tensioner.

• reduces maintenance & mechanical engine noise
• special cam chain "sliders" reduce internal frictional losses.

Lightweight hollow intake & exhaust camshafts.

• provide a broad power band well suited to enduro racing or serious recreational riding

Lightweight, ceramic composite coated aluminum cylinder.

• reduced weight (no sleeve or heavy liner) plating is sprayed directly on the aluminum block
• ceramic coating ensures faster, more uniform heat dissipation
• coating enhances the thin film of oil between the cylinder & piston, reducing friction & increasing power

Special cylinder "cutaways" allow air "trapped" under the piston to enter a side chamber (or cutaway).

• reduces horsepower-robbing "pumping losses"

Crankcase also utilizes cutaways which match the cutaways in the cylinder for maximum efficiency.

• reduces horsepower-robbing "pumping losses"

Lightweight, short-skirt, forged aluminum piston.

• lightweight design means faster throttle response
• reduced mechanical vibration for excellent durability
• special coating on piston skirt reduces friction

Piston oil cooler jet nozzle directs oil to the desired portion of the cylinder, rod & underside of piston.

• reduces piston, cylinder & rod temperatures for excellent durability

YZ450F crankshaft & connecting rod feature a carburizing process for excellent durability.

Lightweight, gear-driven counterbalancer shaft.

• reduces vibration for improved rider comfort & reduces rider fatigue

5-speed, wide ratio transmission utilizes a 2-bar, floating shift guide system & a 14 mm shift shaft.

• smooth, positive shifts
• good durability in the event of a crash (14 mm shift shaft)
• optimized ratios for good performance in difficult sections & solid top end speed for fast sections

Heavy duty, multi-plate, clutch with quick access magnesium outer cover.

• clutch is designed for the rigours of enduro riding
• clutch action is light to reduce hand fatigue during extended races / rides
• quick access outer cover provides fast & easy clutch access

44mm Keihin throttle body fuel injection system.

• 12-hole injector
• maximizes fuel atomization for more complete combustion & excellent power delivery
• FI settings are specific to enduro racing / riding
• FI benefits include automatic adjustments to insure the optimum fuel - air ratio regardless of outside air temperature & altitude
• other benefits include excellent starting & excellent throttle response
• cold start knob also doubles as an idle adjuster

Optional, compact, hand held "GYTR Power Tuner" allows tailoring of both fuel injection duration & ignition mapping.

• 9- different setting points can be accessed for both fuel duration & ignition maps
• maps can be stored & shared with other Power Tuners if desired
• easy access GYTR Power Tuner connector port
  NOTE: Competition Only Kit ECU is required for Power Tuner use on the WR450F

Forward mounted air box features a washable, dual-stage, foam air filter.

• No tools required to access air filter

Wet sump lubrication system.

• reduces weight (no remote oil tank or oil lines)
• eases maintenance (easier & faster oil changes)

Easy access "cartridge-type" oil filter for fast, easy oil changes.

Lightweight, single-core, dual radiators with electric cooling fan.

• standard cooling fan maintains consistent engine temperatures during slow speed, technical riding
• radiator fin pitch is optimized for good air flow even at slow speeds

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 to power the FI system.

Lightweight, wrap-around exhaust system based on YZ450F design.

• exits from the rear of the engine & circles cylinder body
• 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 / stainless steel muffler (aka silencer).

• multi-expansion design
• spark arrestor equipped

Chassis / Suspension

• YZ450F based, compact, lightweight bilateral beam aluminum frame.
• centralizes mass for exceptional handling & manoeuverability
• frame offers an optimum rigidity balance between strength, rigidity & tuned flex, plus excellent shock absorbing qualities
• frame features mounting tabs for accessory under engine skid plate (quick installation)

Lightweight, tapered aluminum swingarm.

• lightweight design reduces unsprung weight for optimum suspension performance
• excellent rear wheel traction & control

Lightweight detachable rear sub frame.

• constructed of square-section, lightweight aluminum pipe with no bends
• allows easy access when servicing rear suspension components

YZ450F-based, 48mm, adjustable, inverted, Kayaba "SSS" cartridge fork with 310mm (12.2") of wheel travel.

• speed-sensitive damping provides exceptional balance between handling and bump absorption
• friction-reducing coating on inner tubes
• compression and rebound damping adjustability
• optional fork springs are available through GYPA
• helps prevent aerated fork oil from entering the inner damper assembly and degrading its damping abilities
• the inner damper is pressurized, eliminating bubbles forming in the oil
• 22 mm front axle
• Transfer Control Valve (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.

YZ450F-based, Monocross link rear suspension features a fully adjustable Kayaba piggyback shock with 318 mm (12.5") of wheel travel.

• shock valving & settings are tailored for enduro riding conditions
• revised rebound damping & high-speed compression settings
• separate adjusters for high- and low-speed compression damping
• shock is in line with the center axis of the frame for excellent control
• shock adjustments include: threaded spring preload, 20-way low-speed compression damping, 2 turns of high speed compression damping & 30-way rebound damping

270 mm floating front wave-style disc & compact twin-piston Nissin caliper.

• wave design reduces weight & improves cooling

Shorty-style adjustable front brake lever can be adjusted to fit various hand sizes.

245 mm rear disc brake features a wave-style disc & single-piston Nissin caliper & master cylinder.

Rear caliper & lower portion of the disc are protected by heavy duty plastic protectors.

Lightweight, plastic resin 7.9-litre fuel tank

• tank is positioned under the seat to reduce centre of gravity and centralize mass for exceptional handling and a lightweight feeling
• compact in-tank electric fuel pump

Adjustable handlebar holders offer a total of 4 different positions with an adjustment range of 30 mm (1.2").

• suits wide variety of rider sizes
• handlebar holders are rubber mounted for reduced vibration & improved rider comfort

Compact bodywork with embedded graphics

• Narrow bodywork design optimizes rider mobility and enhances the lightweight feel and look of the YZ450F
• flat design, "minimal" bodywork allows for fast, easy rider movements and a natural riding position
• minimal design aids in keeping the bodywork looking good longer (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.

• seat is narrow in the fuel tank for ideal knee grip and easy rider movements
• front of seat features a quick remove "cap cover" to access the fuel cap

Rugged Excel rims fitted with Dunlop tires.

• excellent durability and strength
• 18-inch rear wheel improves puncture resistance compared to 19-inch design
• Dunlop tires MX3SF & MX3S tires - 80/100-21 51M front, 120/90-18 65M (rear)

Lightweight digital meter assembly.

• functions include: speedometer, odometer, dual trip meters & clock in the basic mode
• "race mode" features pace management functions including; timer & distance compensating trip meter
• warning lights for engine trouble (FI system) & low fuel

Stylish, slim design 35-watt headlight.

• headlight beam is adjustable up & down

Brilliant LED rear taillight.

Details

• Heavy-duty plastic engine skid plate
• Convenient oil level sight glass
• Lightweight, extra wide foot pegs
• Folding shift lever tip
• Heavy-duty rubber swingarm protector
• Lightweight chain guide reduces chance of chain derailment & helps protect rear sprocket
• Heavy duty sealed chain
• Sealed, no-spill, gel-type, low-maintenance battery