2008 Yamaha YZ450F, 2008 Yamaha YZ450F - 2008 Yamaha YZ450F -Renthal fatbars -FMF Powercore exhaust OUR MOST POWERFUL, MOST FLICKABLE 450 EVER. The bike that started the four-stroke revolution keeps moving forward with chassis and engine refinements that ensure the five-titanium-valved YZ450F remains at the head of the open-class pack.