- An all-new light and strong aluminum frame repositions the engine for great mass centralization and fantastic handling.
- A special 50th anniversary model and sharp, new styling keeps the YZ450F at the front of the pack in the looks department, too.
- New, five-speed gearbox squeezes even more performance from the mighty five-titanium-valved 450.
- Upgraded suspension components at both ends, including a titanium shock spring which provide great handling and ride comfort.
- Trick new bits include a light, strong ProTaper aluminum handlebar in adjustable clamps and a trick new exhaust system.
New for 2006:
- New, close-ratio five-speed transmission provides more performance in a wider range of riding environments.
- All-new aluminum frame is an extensively tested combination of castings, extrusions, forgings and aluminum tubing — all carefully put together to produce a chassis that takes legendary YZ handling to the next level.
- Speed-Sensitive System 48mm Kayaba fork move the TCV (transfer control valves) above the fork springs, so that damping force is now controlled by piston speed; that prevents mid-stroke damping force changes, for a smoother, more precise ride.
- Titanium-sprung four-way adjustable rear shock rod diameter is 2mm bigger. New, Kashima coating reduces friction for fantastic compliance and great handling.
- Carburetion and exhaust changes let the 449cc four-stroke breathe free for even greater power production.
- Changing the cylinder head angle and moving the dry sump oil tank inside the front of the crankcase improves overall balance and handling and eliminates external oil lines.
- Redesigned piston, crankshaft and connecting rod for increased performance and durability. An oil jet now directs oil at the piston bottom for increased cooling.
- 449cc five-valve DOHC liquid-cooled beast is still the most powerful thing in 250-Class MX.
- 39mm Keihin FCR flat-slide carburetor with throttle position sensor (TPS) and leak jet delivers precise fuel/air mixture and instant throttle response.
- Revised CDI ignition keeps that amazingly broad and deep powerband hard-hitting, yet controllable.
- Lightweight, titanium valves and load-reduced springs are super light, minimizing reciprocating mass for fast-revving, hard-hitting power delivery across the rev range.
- Additional weight-saving engine features include: small-design cam chain tensioner and oil pump, aluminum oil hose, all-titanium exhaust header, flange, bracket and heat shield and light CDI ignition unit.
- Primary kickstarting with automatic decompression and convenient handlebar-mounted hot start lever ensures easy restarts. A new kickstart lever provides efficient starting, hot or cold.
- Kick pinion gear is separate from the primary driven gear for smoother clutch engagement.
- Large-capacity radiator provides outstanding cooling efficiency.
- 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 pipe 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, 250mm front and 245mm rears discs, deliver strong stopping power with progressive feel.
- Premium Dunlop knobbies provide unbeatable, competition-spec traction and great wear.
- Lightweight 21-inch front and 19-inch rear Excel rims are exceptionally durable and reduce unsprung weight.
- “Gripper” style seat cover offers excellent feel and control.
- Wide, cleated, folding titanium footpegs are light, strong, and provide excellent comfort, grip and ground clearance.
- Trick, works-style clutch lever features oversize barrel adjuster for easy, on-the-fly adjustability of lever/cable play.
- Cleated rear brake lever and folding shift lever tip offer superb grip and excellent durability.
- Repackable exhaust silencer.
- Durable, comfortable handlebar grips.
- Stainless steel clutch cable for longer life.