2001 Arctic Cat ATVs factory service and repair manual, Page 214Get this manual
Fig3-788
Measuring Rocker Arm Shafts (Outside Diameter)
1Using micrometer, measure the outside diameter of the rocker arm shaft2Acceptable outside diameter range is 11.977-11.995 mm (0.4715-0.4722 in for the 250300 cc and 11.973-11.984 mm (0.4714-0.4718 in for the 400500 ccInstalling Valves
1Apply grease to the inside surface of the valve seals; then place lower spring seat and valve guide seal over each valve guideFig3-790
NOTE: On the 400500 cc, repeat procedure on the remaining intake valveFig3-789