Features and Technical detail:
Engine
Engine Type    DOHC 4-stroke; 5 titanium valves
Displacement    449cc
Bore x Stroke    95.0mm x 63.4mm
Engine Cooling    Liquid
Fuel System    Yamaha Fuel injection (YFI), 42mm
Starting System    Electric
Chassis
Front Suspension    Independent double wishbone w/Kashima coated piggyback shocks; high/low speed compression, rebound and threaded preload adjustment
Front Travel    9.8 in.
Front Brake Type    Dual hydraulic disc
Front Tires    AT21 x 7-10 Maxxis?
Rear Travel    11 in.
Rear Suspension    Cast aluminum swingarm w/piggyback shocks; high/low speed compression, rebound and threaded preload adjustment
Rear Brake Type    Wave-style hydraulic disc
Rear Tires    AT20 x 10-9 Maxxis?
Dimensions/Capacities
Dry Weight    Curb Weight: 405 lb.
Fuel Capacity    2.6 gal.
Ground Clearance    9.3 in.
Machine Dimensions (LxWxH)    70.7 in. x 48.8 in. x 41.9 in.
Wheelbase    50.0 in.
Drive Train
Drive Train    2WD
Final Drive    O-ring chain
Transmission    5-speed; assist and slipper clutch
General
Lighting    Dual 30W Krypton headlights and LED brake light

Top Features

    Race-Ready Engine: the YFZ450R is the most technologically advanced sport ATV on the market today. It is simply the top of the line " racing" level Sport ATV. It combines a high-tech, quick-revving, titanium five-valve, 449cc fuel-injected engine with a lightweight, professional-caliber cast aluminum/steel chassis. the power/chassis combination will make for a championship-winning machine time and time again.
    Advanced Frame: the YFZ450R is motocross ready. the weldless frame is designed from lightweight aluminum, with a tension-steel bottom frame that lets the engine sit lower for excellent mass centralization. Suspension components and settings reduce weight while providing light, sharp handling and rider comfort.
    Aggressive SE Style: Bodywork is designed for great ergonomics and rider comfort, with more room to hang off in the corners, and the seat shape is padded in just the right places to improve lap times. Body panels come off easily without tools for service, and a dealer-installed GYTR? Grab bar highlights the unique SE graphics package.
    Advanced Cylinder Head: the 449cc engine uses titanium five-valve cylinder head technology designed to deliver abundant power in the MID-range to top end, with more " hit" feeling right off idle. the higher compression ratio further improves overall engine performance.
    Fuel Injection: the YFZ450R incorporates Yamaha Fuel Injection for precise fuel delivery. with a big 42mm Mikuni? Throttle body and 12-hole injector, this system provides exceptional atomization of the fuel for maximum power. the system also includes ISC (Idle Speed Control) for easy, reliable start-up and warming.
    Assist and Slipper Clutch: the industry's first assist and slipper clutch on a Sport ATV reduces clutch lever effort by about 25% for less fatigue while at the same time increasing clutch plate pressure for positive engagement. Additionally, this new clutch system reduces the engine braking effect, which allows faster cornering, particularly when downshifting, and also allows the suspension to absorb bumps better during braking.

Engine Features

    Powerful Motor: the fuel-injected 449cc engine has superb power characteristics. Power delivery is smooth and strong off the line with lots of midrange to top-end power.
    Compact Counterbalanced Engine: the crankcase holds a crankshaft that's ready to handle the increased demands of the racer, as well as a counterbalancer to reduce vibration. the crankcase also houses the oil tank, which helps to centralize mass for unmatched handling while making maintenance easier.
    Tuned Camshafts: Camshafts have been revised to help maximize the engine's impressive power output from off the line all the way up to the top end.

Chassis/Suspension

    Race-Ready Ergonomics: the body configuration allows more room for the racer to move around during the moto. the seat is narrow in the front, yet wide and padded in the rear to reduce fatigue.
    Durable Rigid Wheels: the wheels have been designed with the inner lip rolled in. this increases the rigidity, allowing a reduction in weight while maintaining strength.
    Wide Track and Maxxis? Tires: Wheels are set motocross-spec wide, near the maximum allowable 50 inches, for great cornering speed. Maxxis? Tires help provide excellent handling and control. At 20 inches in the rear and 21 inches in the front, they provide better ground clearance than the competition.
    Adjustable Handlebar: Large diameter, tapered handlebar reduces vibration and are mounted on 4-way clamps for exceptional adjustability. the two sets of holes in the handlebar crown and the eccentric clamps allow a rider to choose the standard setting, 10mm or 20mm forward, or 10mm back.
    Wide Footpegs: Foot pegs are a generous 2.6 inches wide, something riders will appreciate every time they want to get up on the pegs.
    Advanced Frame: the frame is a combination of aluminum and steel for light weight. the frame member under the engine is steel, used for its combination of strength and low profile. this allows the engine to sit lower overall for excellent mass centralization for unmatched handling. the aluminum frame is bolted together, rather than welded, for maximum durability.
    Long A-Arm Suspension: the front frame is as narrow as possible at the A-arm mounting points. this increases the A-arm length and reduces changes in camber as the suspension travels through its full range of motion.
    High-Performance Shocks: the front KYB? Shocks are longer for increased stroke with superb bump absorption and excellent anti-bottoming characteristics, and they have Kashima? Coating for smooth operation. 9.8 inches of wheel travel means this racer is up to even the most challenging tracks.
    Swingarm Rear Suspension: the rear swingarm is crafted of strong, gravity-fed aluminum, and is matched to a fully adjustable 46mm KYB? Piggyback shock for excellent handling. Rear wheel travel is 11.0 inches for comfort even on tough terrain.

Additional Features

    Light Throttle Action: the throttle lever requires low effort - less fatigue during long motos.
    Compact LED Indicators: the discrete panel on the fender in front of the rider gives vital indicators about low fuel, coolant temperature, check engine, and neutral gear via an LED display.

Engine

    Engine Type: 449cc liquid-cooled DOHC 4-stroke; 5 titanium valves
    Bore x Stroke: 95.0mm x 63.4mm
    Compression Ratio: 11.8:1
    Fuel Delivery: Yamaha Fuel injection (YFI), 42mm
    Ignition: TCI: Transistor Controlled Ignition
    Starting System: Electric
    Transmission: 5-speed; assist and slipper clutch
    Final Drive: O-ring chain; 2WD

Chassis

    Suspension / Front: Independent double wishbone w/Kashima coated piggyback shocks; high/low speed compression, rebound and threaded preload adjustment, 9.8-in travel
    Suspension / Rear: Cast aluminum swingarm w/piggyback shocks; high/low speed compression, rebound and threaded preload adjustment, 11.0-in travel
    Brakes / Front: Dual hydraulic disc
    Brakes / Rear: Wave-style hydraulic disc
    Tires / Front: AT21 x 7-10 Maxxis?
    Tires / Rear: AT20 x 10-9 Maxxis?

Dimensions

    L x W x H: 70.7 in. x 48.8 in. x 41.9 in.
    Seat Height: 31.9 in.
    Wheelbase: 50.0 in.
    Ground Clearance: 9.3 in.
    Fuel Capacity: 2.6 gal.
    Wet Weight: 405 lb.
    Lighting: Dual 30W Krypton headlights and LED brake light