December 6th, 2017. These high-quality, great-value and stylish OEM replacement parts for the Yamaha YFZ450R are available from ATV’s Only. Precision-machined from 6061 T-6 aluminium, both plugs and caps are polished to a mirror finish prior to anodizing, which results in a brilliant look, and then laser-engraved with the WC logo. Made in the USA and available in fade-resistant blue, red or black. The engine plugs retail at £45.02, and the oil filler caps are £20.41.