Athena P400485100016 478cc Big Bore Cylinder Kit (98mm Bore) - Forged Piston Performance Upgrade, Converts 450cc to 478cc, Compatible with Yamaha YFZ450 ATV, YZ450F, and WR450F Safe or just replacing a worn-out

or just replacing a worn-out unit

the Polisport replica plastics have a glossy finish and colors that perfectly match the stock parts and make your dirt bike look great

Polisport's rear fenders are produced with Polisport's exclusive technologies

keeping your other hand free while working

Athena P400485100016 478cc Big Bore Cylinder Kit (98mm Bore) - Forged Piston Performance Upgrade, Converts 450cc to 478cc, Compatible with Yamaha YFZ450 ATV, YZ450F, and WR450F Safe or just replacing a worn-outUPGRADE YOUR RIDE TO THE NEXT LEVEL OF PERFORMANCE Extract massive power, aggressive low end torque, and unmatched acceleration from your 450cc four stroke engine with the Athena Big Bore Cylinder Kit (Part No. P400485100016), a premium race proven package engineered in Italy to seamlessly convert your factory setup into a high revving, high output 478cc powerhouse. Entirely cast from high grade aluminum and treated with a specialized Motor Nicksil