2012 Sportsman 400/500 and EFI Tractor Service Manual 9923412, Page 80Get this manual
ENGINE 4Measure free length of spring with Vernier caliperCheck spring for squarenessCompare to specificationsReplace spring if either measurement is out of specification4Inspect split keeper groove for wear or flaring of the keeper seat area (B)NOTE: The valves cannot be re-faced or end groundThey must be replaced if worn, bent, or damaged5Measure diameter of valve stem with micrometer in three places and in two different directions (six measurements total)Compare to specificationsMeasure valve stem in several places
5Remove valve sealsCAUTION: Replace seals whenever the cylinder head is disassembledHardened, cracked or worn valve seals will cause excessive oil consumption and carbon buildup
Valve Stem Diameter: Intake: .2343-.2348" (5.950-5.965 mm) Exhaust: .2341-.2346" (5.945-5.960 mm) 6Measure valve guide inside diameter at the top middle and end of the guide using small hole gauge and micrometerMeasure in two directions, front to back and side to side