YZ450

The Yamaha YZ450F is a four-stroke racing motocross bike built by Yamaha Motor Corporation. It was the successor to the previous YZ426F which was discontinued in 2003. It is credited by Cycle World and Dirt Rider magazines as the bike that started the four-stroke dirt bike revolution.[1][2] The 2006 YZ250F and YZ450F were the first production motorcycles equipped with titanium suspension springs.[3]