Vertex's latest generation two-stroke and four-stroke piston rings are nitride coated or chrome plated, increasing wear resistance and extending durability. Vertex piston rings are exact OEM replacements and can be used with your existing OEM piston. Replacement two-stroke piston rings sold individually; four-stroke piston rings sold as a set. YAMAHA WR450F 2003YAMAHA WR450F 2004YAMAHA WR450F 2005YAMAHA WR450F 2006YAMAHA WR450F 2007YAMAHA WR450F 2008YAMAHA WR450F 2009YAMAHA WR450F 2010YAMAHA WR450F 2011YAMAHA WR450F 2012YAMAHA WR450F 2013YAMAHA WR450F 2014YAMAHA WR450F 2015YAMAHA YFZ450 R 2004YAMAHA YFZ450 R 2005YAMAHA YFZ450 R 2006YAMAHA YFZ450 R 2007YAMAHA YFZ450 R 2008YAMAHA YFZ450 R 2009YAMAHA YFZ450 R 2010YAMAHA YFZ450 R 2011YAMAHA YFZ450 R 2012YAMAHA YFZ450 R 2013YAMAHA YFZ450 R 2014YAMAHA YFZ450 R 2015YAMAHA YFZ450 R 2016YAMAHA YFZ450 R 2017YAMAHA YZ450F 2003YAMAHA YZ450F 2004YAMAHA YZ450F 2005YAMAHA YZ450F 2006YAMAHA YZ450F 2007YAMAHA YZ450F 2008YAMAHA YZ450F 2009