All new for 2011, Suzuki’s RM-Z450 Dirt Bike has been fine tuned to be a potent machine. It also boasts a series of updates that make it ride smoother and easier to maintain. But more importantly, the RM-Z450 is a cutting-edge bike that doesn’t let anything stand it its way. Powered by a 449cc four-stroke, liquid-cooled, DOHC, four-valve, fuel-injected engine, this Suzuki dirt bike delivers phenomenal idle-to-redline thrust and it meets a stricter AMA noise limit (94db) while keeping smooth engine output. Other features include 5-speed transmission, gripper seat, race-inspired disc rotors, two-tone radiator and Showa piggyback-reservoir rear shock. Race away on one for $8,149. Suzuki.