New for the 2003 Yamaha YZ450F:

• Received an extra 23ccs of power, lost 13 pounds and received an all-new frame and handling updates.
• All-new, flatter fuel tank, seat radiator shrouds.
• All-new four-speed transmission (down from five), reducing weight and increasing strength.
• All-new, convenient handlebar-mounted hot-start system and all-new automatic decompression system.
• Newly designed exhaust pipe, now titanium verses steel.
• Redesigned air filter case.
• Redesigned oil pump.
• Smaller cylinder head.
• All-new crankshaft.
• All-new tapered swingarm in the rear reduces weight and increasing rigidity for a more compliant rear suspension.
• New rear suspension linking ratio and enhanced damping.
• Recalibrated fork settings.
• All-new light-weight front and rear master cylinders and calipers, combined with a 250mm floating disc brake up front and 245mm rear disc.