Arctic Cat 660 cc Service Manual page 43

NOTE: Do not grind the valves. If a valve is dam-
aged, it must be replaced.
3. Lubricate each valve stem with lightweight oil;
then apply a small amount of valve lapping
compound to the entire seating face of each valve.
4. Attach the suction cup of a valve lapping tool to
the head of the valve.
5. Rotate the valve until the valve and seat are evenly
polished.
6. Clean all compound residue from the valve and
seat.
Valve Seat Repair
NOTE: If the valve seat is beyond servicing, the
cylinder must be replaced.
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GEN-0024
GEN-0025
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A valve seat not producing a uniform contact with its
valve or showing a seating contact width that is not
within the specified range must be repaired by cutting.
1. Insert the expandable pilot shaft into a valve
guide; then install a 45° cutter onto the pilot shaft.
Grind the valve seat by turning the cutter 1-2 turns
using a T-handle.
2. Remove the pilot shaft and cutter; then coat the
valve seat with a blueing compound and insert the
valve into the valve guide. Rotate the valve while
tapping the valve head; then remove the valve and
inspect the valve seat and valve face for proper
width.
3. The pattern produced on the seating surface of the
valve and valve seat must be a continuous ring
without any break and the width of the pattern
must be within specifications. Grind the valve seat
width to 0.8-1.0 mm (0.032-0.039 in.).
4. Inspect for dents or burning on the valve seat and,
if necessary, rotate the 45° cutter another turn to
smooth out the valve seat.
! CAUTION
Do not over-grind the valve seats. Grind the
seats only as necessary to ensure a continuous
contact with the valve seating surface.
5. If the position of the valve face width is low, grind
the valve seat using a 75° cutter to raise the
position of the valve seat. If the position of the
valve face width is high, grind the valve seat using
a 15° cutter to lower the position of the valve seat.
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