Wiseco VIS029 Premium Stainless Steel Intake Valve Fits: Yamaha YFM660R Raptor 2001-2005, YFM660R Grizzly 2002-2008 Wiseco's stainless steel valves are made from premium materials and manufactured to the highest quality specifications A one-piece, forged construction offers high strength and fatigue properties Chromium nitride coating offering surface hardness and wear resistance Each design is a drop-in application and requires no piston or head modifications and will work with stock springs and valve-train