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- 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 aluminium 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.
- 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.
- 449cc five-valve DOHC liquid-cooled engine is super-powerful yet tractable.
- 39mm Keihin FCR flat-slide carburettor 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 kick-starting with automatic decompression and convenient, handlebar-mounted hot start lever ensures easy restarts.
- Large-capacity radiator is reinforced for greater strength.
- Extensively tested aluminium 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 aluminium, part plastic) engine protector plates and thin-walled engine guard construction.
- Removable aluminium rear subframe constructed of square-section tubing for lightweight and easy maintenance.
- Lightweight front-wheel hub for reduced unsprung weight and increased durability.
- Lightweight front- and rear-brake callipers with aluminium pistons and anti-bubble front master cylinder; wave-style rotors reduce unsprung weight and deliver strong stopping power.
- “Gripper” style seat cover gives excellent feel and control.
- ProTaper aluminium 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.
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