The Yamaha YZ450F is a four-stroke racing motocross bike built by Yamaha Motor Corporation. It is credited by Cycle World and Dirt Rider magazines as the bike that started the four-stroke dirt bike revolution. It is a replacement for the YZ250, which is slowly being phased out. The 2006 YZ250F and YZ450F were the first production motorcycles equipped with titanium suspension springs.
The WR450F is the enduro version of the YZ450F.
Read more about Yamaha YZ450F: Introduction, First Generation: YZ400F - 1998-2000, Second Generation: YZ426F - 2000-2002, Third Generation: Yamaha YZ450F - 2003-2005, Fourth Generation: Yamaha YZ450F 2006-2009, Fifth Generation: Yamaha YZ450F 2010