New for the 2006 Yamaha YZ450F on 4Strokes.com

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.
Trick new bits include a light, strong ProTaper aluminum handlebar in adjustable clamps and a trick new exhaust system.
A special 50th anniversary model.