2003 Yamaha YFM400FAR Kodiak Factory Service Manual, Page 143Get this manual
CAMSHAFT, ROCKER ARMS AND VALVES
2.Check: Rocker arms Rocker arm shafts Damagewear Replace Checking steps: Check the two contact areas on the rocker arms for signs of abnormal wear1) Rocker arm shaft hole 2) Camshaft lobe contact surface Excessive wear ReplaceG Check the surface of the rocker arm shaftsBlue discolorationpittingscratches Replacecheck lubricationG Measure the inside diameter of the rocker arm holesOut of specification ReplaceRocker arm inside diameter: 12.00012.018 mm (0.47240.4731 in)