Yamaha YZ450F - Third Generation: Yamaha YZ450F - 2003-2005

2003-2005

For 2003, the YZF received the biggest update in its history. First, the engine displacement was increased to 449 cc, producing over 52 horsepower, in compliance to the new AMA Motocross maximum displacement rule. Next, the frame and plastic were all updated for a new, sleeker look. Additionally, the YZ's weight was engineered from its original 250 pounds down to 233 pounds. The new YZF also had a gearing change, going from a traditional 5-speed to a 4-speed transmission. The bike made tremendous power; however, many thought that the bike had too much power for a motocross track.