First Look: 2008 Yamaha YZ450F


You can click the following link to check out a gallery of photos of the 2008 Yamaha YZ450F.

Key Features:


  • The bike that started the four-stroke revolution benefits from chassis and engine refinements that ensure the five-titanium-valved YZ450F remains at the head of the open-class pack.
  • Subtle modifications to the aluminum frame and suspension mean light, precise, confident handling at any speed.
  • New head and exhaust design delivers stronger low- to midrange power without sacrificing top end power.
  • Ready to race straight out of the crate—with a ProTaper aluminum handlebar in adjustable clamps, titanium shock spring, gripper seat, Excel rims, etc.
  • Five-speed gearbox provides maximum flexibility and the right gear for a wide range of riding environments.

     


New for 2008:


  • Revised intake port shapes, and revised intake and exhaust cam profiles increase combustion efficiency for improved torque and throttle response in the low- to mid-rpm range.
  • Micron-level adjustment of piston external diameter minimizes piston-to-cylinder clearance for reduced vibration and mechanical noise.
  • Adjustment of gear backlash between clutch primary gears and balancer gears achieves further mechanical noise reduction.
  • A new, larger-diameter titanium exhaust header with revised taper characteristics enhances exhaust efficiency.
  • First “punched cone” muffler ever on a production bike allows 35 percent length reduction and 270-gram weight reduction while meeting AMA noise regulations.
  • Matte black crankcase covers: light, strong and cool-looking.
  • Steering head pipe and steering stem are 5mm shorter; lower forged triple steering clamp is lighter—for enhanced handling feel. Swingarm pivot stiffness is revised to complement front-end changes and further lighten and improve steering/handling.
  • Changes to the shape of the outer fork tubes and revised internals result in improved damping and a smoother ride.
  • Optimized linkage ratio provides a smoother ride and enhanced rear wheel traction.
  • New, YZ250F-style, front-brake caliper (-220 grams) and a lighter disc remove unsprung weight and provide excellent stopping power. A new axle and collar remove additional weight.
  • A 120/80-19 rear Dunlop D756 knobby replaces the 110/90-19 for even more traction. A D742FA replaces the D739FAL front tire.
  • Wider footpegs provide excellent boot traction and rider comfort.

     


Engine:


  • 449cc five-valve DOHC liquid-cooled engine is super-powerful yet tractable.
  • 39mm Keihin FCR flat-slide carburetor with throttle position sensor (TPS) and leak jet delivers precise fuel/air mixture and instant throttle response.
  • Lightweight titanium valves and load-reduced springs minimize reciprocating mass for fast-revving, hard-hitting power delivery across the rev range.
  • Primary kickstarting with automatic decompression and convenient, handlebar-mounted hot start lever ensures easy restarts.
  • Large-capacity radiator is reinforced for greater strength.

     


Chassis/Suspension:


  • Extensively tested aluminum frame uses a mix of alloy castings, forgings and extrusions to produce a tuned-flex frame that makes the YZ the finest-handling motocross bike ever.
  • Speed-Sensitive System 48mm Kayaba fork places transfer control valves (TCV) above the fork springs, so that damping force is controlled by piston speed: Eliminating mid-stroke damping force changes provides a smoother, more precise ride.
  • Titanium-sprung, four-way adjustable rear shock with Kashima-coated internals reduces friction for fantastic compliance and great handling.
  • More weight savings come via two-piece (part aluminum, part plastic) engine protector plates and thin-walled engine guard construction.
  • Removable aluminum rear subframe constructed of square-section tubing for light weight and easy maintenance.
  • Lightweight front-wheel hub for reduced unsprung weight and increased durability.
  • Lightweight front- and rear-brake calipers with aluminum pistons and anti-bubble front master cylinder; wave-style rotors reduce unsprung weight and deliver strong stopping power.

     


Additional Features:


  • “Gripper” style seat cover gives excellent feel and control.
  • ProTaper aluminum handlebar for strength and performance.
  • Works-style clutch lever features oversize barrel adjuster for easy, on-the-fly adjustability of lever/cable play.
  • Repackable exhaust silencer.
  • Durable, comfortable handlebar grips.

     

























































  • MSRP*


    $7,099 (Team Yamaha Blue/White)
    Available from July 2007

    $7,199 (White/Red)
    Available from July 2007


    Engine

     

    Type

    449cc liquid-cooled DOHC 4-stroke; 5 titanium valves

    Bore x Stroke

    95.0 x 63.4mm

    Compression Ratio

    12.3:1

    Carburetion

    FCR-MX39 x 1

    Ignition

    CDI

    Transmission

    Constant-mesh 5-speed; multiplate wet clutch

    Final Drive

    Chain Drive

    Chassis

     

    Suspension/Front

    Speed-Sensitive System inverted fork; fully adjustable, 11.8-in travel

    Suspension/Rear

    Fully adjustable single shock; 12.3-in travel

    Brakes/Front

    Hydraulic single disc brake, 250mm

    Brakes/Rear

    Hydraulic single disc brake, 245mm

    Tires/Front

    80/100-21-51M

    Tires/Rear

    120/80-19-62M

    Dimensions

     

    Length

    86.4 in

    Width

    32.5 in

    Height

    51.4 in

    Seat Height

    38.9 in

    Wheelbase

    58.8 in

    Ground Clearance

    14.7 in

    Dry Weight

    219 lb

    Fuel Capacity

    1.8 gal

    Other

     

    Warranty

    30 Day (Limited Factory Warranty)

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