ENGINE

• Revised, “reversed”, liquid-cooled, 449 cc, DOHC, 4-valve (titanium), fuel injected, single with electric start.
• All new electric starting.
  • super convenient electric starting means faster re-starts & significantly reduced rider fatigue
  • compact electric starter powered by a lightweight lithium ion battery
• “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 shot intake path provides optimum fuel / air / exhaust 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)
• Rearward slanted, reversed cylinder design centralizes mass.
  • rearward slant has been revised
  • rearward slant moves a significant amount of rotating weight toward the centre of the chassis, centralizing mass for light, agile handling
• Revised, 4-valve cylinder head features a new 12.8:1 compression ratio.
  • compact combustion chamber provides optimum combustion speed while also reducing heat & power losses
  • 37 mm titanium intake valves & 30.5 mm titanium exhaust valves
  • 4-valve design offers optimum flow for excellent power & torque
  • intake port shape has been revised for 2018
  • re-located engine mounting “bosses” have been moved to the rear of the cylinder head
  • new aluminum upper engine mounts
• New long design electrode spark plug.
  • moves the spark plug tip deeper into the combustion chamber
  • new spark plug cap holder (helps prevent plug cap from being dislodged)
• Revised high lift intake & exhaust cams & valve springs.
  • intake & exhaust cam profiles & cam timing have been revised for increased power output
  • valve spring size & rates have been revised to match the revised cams
  • valve spring rates are optimized to reduce friction related power losses
• Lightweight titanium valves.
  • titanium valves reduce weight & improve performance… titanium valves are 40 to 45 % lighter than steel valves
  • reduced valve weight improves valve train reliability & longevity
  • reduced reciprocating weight allows for a higher rpm limit & better control of the valves
• Automatic cam chain tensioner.
  • reduces maintenance & mechanical engine noise
  • special cam chain “sliders” reduce internal frictional losses
• Lightweight, ceramic composite plated “liner-less” aluminum cylinder.
  • reduced weight (no sleeve or heavy liner) … plating is sprayed directly on the aluminum block
  • ceramic coating insures faster, more uniform heat dissipation
  • ceramic coating enhances the thin film of oil between the cylinder & piston, reducing friction & increasing power
• Cylinder is “offset” relative to the crankshaft (to exhaust side).
  • reduces frictional losses between piston & cylinder wall during the power stroke
• Cylinder “cutaways” allow air “trapped” under the piston to enter a side chamber (or cutaway).
  • reduces horsepower-robbing “pumping losses”
• Crankcase also utilizes special “cutaways”.
  • reduces horsepower-robbing “pumping losses”
  • crankcase cutaways match cylinder cutaways for maximum efficiency
• New, lightweight, short-skirt, forged aluminum piston & piston pin.
  • new piston design increases the compression ratio from 12.5:1 to 12.8:1
  • piston weight is reduced by 6 grams & features new under side ribs for additional strength
  • lightweight design means faster throttle response & reduced mechanical vibration for excellent durability
  • New, DL (diamond like) coating on piston pin & special coating on piston skirt reduces frictional losses
• Piston oil cooler jet nozzle directs oil to the cylinder, rod & underside of piston.
  • reduces piston, cylinder & rod temperatures for excellent durability
• Carburized connecting rod for excellent durability.
  • carburization is a type of heat treating that adds strength & hardness
• Lightweight gear driven balancer shaft.
  • reduces vibration for improved rider comfort & reduced rider fatigue
• Revised, heavy duty clutch with quick access magnesium outer cover & on the fly “barrel adjuster.”
  • revised pressure plate features new reinforcing ribs for improved clutch feeling
  • revised clutch springs & specially machined steel plates
  • quick access outer cover provides fast & easy clutch access
  • light lever pull for reduced hand fatigue during a long moto
  • works-style race-spec “barrel adjuster” for on-the-fly clutch lever free play adjustments.
• Revised, 5-speed transmission utilizes a 2-bar, floating shift guide system & a 14 mm shift shaft.
  • newly designed 2nd, 3rd & 4th gears are wider to match the increased engine power
  • floating shift guide system provides smooth, positive shifts
  • 14 mm shift shaft provides good durability in the event of a crash
  • see spec page for gear ratios (ratios are unchanged Vs. 2017)
• New, lightweight, 44 mm Mikuni throttle body fuel injection system.
  • 12-hole injector maximizes fuel atomization for more complete combustion & excellent power delivery
  • FI benefits include automatic adjustments to insure the optimum fuel — air ratio regardless of outside air temperature & altitude
  • other benefits include excellent throttle response & starting
  • cold start knob (FID) also doubles as an idle adjuster
• The injector spray pattern, spray direction and the 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.
• All new, Smartphone based, wire-less, “Power Tuner” with expanded functions.
  • super convenient, Smartphone based power tuner
  • no “hard” link required between the unit & Smartphone… wireless signal via Wi-Fi
  • app is free… will work with either ISO or Android platforms
  • receiving communication control unit (CCU) is located under left side cover of bike
  • expanded adjustment range… 16 settings for both fuel injection duration & ignition timing
  • new “real time” machine monitoring function (engine rpm, throttle angle, battery voltage, coolant temp, intake air temp, outside air pressure, etc.)
  • new maintenance function… tracks hours of use for scheduled maintenance
  • new race log function is available to record & save settings from various tracks
  • tuning maps & race logs can be shared
• Revised forward mounted air box with revised washable, dual stage foam air filter.
  • no tools required to access air filter
  • new air box cover with single quick release fastener
  • revised, washable dual stage air filter
• Wet sump lubrication system.
  • reduces weight (no remote oil tank or oil lines)
  • eases maintenance (easier & faster oil changes)
  • oil volume is optimized to reduce oil related drag & weight
• Easy access “cartridge-type” oil filter for fast, easy oil changes.
  • revised, single core, dual radiators provide outstanding cooling efficiency.
  • core size has been increased while upper & lower tank sizes have been decreased
  • actual cooling area of the rads has been increased approx. 4%
  • mounting angle of the rads, rad shrouds & cooling louvers have been revised for increased air flow
• 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
• Revised high capacity AC magneto.
  • smaller, lighter ACM means less engine rotational resistance
• Revised, lightweight, wrap-around exhaust system.
  • exhaust exits from the rear of the cylinder & circles cylinder body
  • revised “1st stage” header has been lengthened to ensure 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 CMRC & AMA regulations
  • new muffler rubber mounting system reduces vibration & improves durability
• Launch control system (LCS).
  • provides smoother, quicker starts with less wheel spin & front wheel lift
  • allows rider to concentrate on clutch control, body position & machine
  • system functions in 1st & 2nd gears only and is disabled when the bike is shifted into 3rd
  • ECU controls the system and adjusts engine rpm to limit wheel spin & wheelies
  • activation button is on the LHS handlebar & features a LED indicator light.
• Special “G” sensor system.
  • shuts down fuel injection system if bike lies on its side for more than 10 seconds
  • helps prevent costly engine damage
  • no special procedure to re-start the bike… just hit the electric start button

CHASSIS/SUSPENSION

• • New, compact, lightweight “Bilateral Beam” aluminum frame.
    • new frame offers an optimum rigidity balance between strength, rigidity & tuned flex, while also providing excellent shock absorbing qualities
    • frame design is new with the steering head moved forward (Vs. last generation) — resulting in a 5 mm longer wheelbase for improved traction & stability
    • new, top frame rails (aka. tank rails) are a straight design (Vs. last generation’s slight S bend)
    • upper engine mounts are moved rearward to provide optimized front frame rigidity & tuned flex
    • swingarm pivot area is wider (Vs. last generation) improving bump stability & traction
  • Revised, lightweight, tapered aluminum swingarm.
    • swingarm is slightly shorter (Vs. 2017) and 3.6% lighter
    • lightweight design reduces unsprung weight for optimum suspension performance
    • excellent rear wheel traction & control
    • 25mm rear axle
  • Lightweight detachable rear sub frame.
    • constructed of square-section, lightweight aluminum pipe with no bends
    • allows easier access when servicing rear suspension components
    • detachable design reduces costs in the event of a loop out
  • Revised upper & lower triple clamps.
    • fork off set is 22 mm (Vs. 25 mm for 2017)
  • New, light weight, high strength, tapered aluminum handlebar.
  • Adjustable handlebar holders offer a total of 4 different handlebar positions with an adjustment range of 30 mm (1.2″).
    • suits wide variety of rider sizes
    • handle bar holders are rubber mounted for reduced vibration & improved rider comfort
  • Revised, 48mm, adjustable, inverted, KYB “SSS” cartridge fork with 310mm (12.2″) of wheel travel.
    • cylinder diameter has been increased from 24 to 25 mm for improved damping
    • mid speed valve is changed from coil spring to “leaf spring” style
    • friction reducing coating on inner tubes for reduced stiction
    • 22 mm front axle
    • front fork adjustments include: compression & 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 & oil chambers)
    • helps prevent aerated fork oil from entering the inner damper assembly & degrading its damping abilities
    • the inner damper is pressurized, eliminating bubbles forming in the oil
  • Fork also features a Transfer Control Valve (TCV).
    • TCV enhances damping from mid to full stroke & improves bottoming characteristics
    • TCV offers more precise control throughout the full suspension stroke
    • 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”.
  • Large “wrap-around” plastic fork protectors provide excellent lower fork tube protection.
    • “self-supporting” design reduces friction for smoother fork operation
  • Revised, Monocross link rear suspension with 317 mm (12.5″) of wheel travel.
    • fully adjustable KYB piggyback shock features a larger sub tank, new lighter spring & revised damping 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, low & high speed compression damping, & rebound damping
  • 270 mm floating front “wave-style” disc & compact Nissin twin piston caliper.
    • wave disc design reduces weight & improves cooling (wave design offer more surface area for better cooling)
    • excellent braking performance
    • “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.
    • revised rear rotor for improved heat resistance
    • rear caliper & lower portion of the disc are protected by heavy duty plastic protectors.
  • New, 6.2 litre lightweight plastic resin fuel tank
    • • tank is positioned under the seat to reduce the centre of gravity & centralizes mass for exceptional handling & a lightweight feeling

    compact in-tank electric fuel pump

  • New, compact body work.
    • newly designed bodywork reduces weight, improves rider mobility & enhances the lightweight feel & look of the YZ450F (new items: front fender/ rad shrouds / air box cover /gas tank / side covers / rear fender)
    • flat design, “minimal” bodywork allows for fast, easy rider movements & a natural riding position
    • minimal design aids in keeping the body work looking good longer (less plastic to scratch or damage)
    • graphics are impregnated directly into the plastic rad shrouds & will not peel off or get damaged by pressure washing
  • Revised, flat design seat.
    • seat is narrower in the fuel tank — seat junction (Vs. ’17 model) for better knee grip & easier rider movements
    • seat is flatter (rear portion) for easier rider movements
    • front of seat features a quick remove “cap cover” to access the fuel cap
  • New, lightweight D.I.D. front & rear rims.
    • new lighter design reduces unsprung weight for optimal suspension performance & handling
    • excellent strength & durability due to new cross sectional rim design
    • front rim size is 1.60 x 21″, rear is 2.15 x 19″
    • rear hub features second bearing on sprocket side for increased rigidity & durability
  • Lithium ion battery.
    • lightweight, compact battery & under seat, lightweight composite battery box
    • special battery management system (BMS) with “self-protection” mode monitors & maintains battery condition

NOTE: Lithium ion batteries must be charged using the correct type of charger. Yamaha recommends using only the Optimate Lithium TM291 battery charger. Do not use a high powered, lead acid charger or an automatic de-sulphating lead acid charger or serious battery damage will occur. Never use jumper cables connected to a lead acid battery to start the engine.

• YDT (Yamaha Diagnostic Tool) easy access, under seat coupler.
  • Yamaha’s exclusive money & time saving diagnostic tool