Valves, Valve Guides, Valve Seats, And Valve Springs - Yamaha XZ550RJ 1982 Service Manual

Cylinder head warpage:
less than 0.03mm (0.0012 in)
Valves, valve guides, valve seats, and valve
springs
Valves
1. Check the valve face and the stem end for
wear. If the valve face and/or the stem end
are pitted or worn, regrind the valve with a
valve refacer. Replace the valve if any di-
mension exceeds the specifications in the il-
lustration.
2. Valve stem wear must be measured and
then combined with valve guide measure-
ments to obtain guide clearance. This
clearance must be within tolerances. If it
exceeds the maximum limit, then replace ei-
ther or both valve and guide, as necessary.
3. Inspect the end of the valve stem. If the end
appears to be "mushroomed" or has a
larger diameter than the rest of the stem,
the valve, valve guide, and oil seal should
be replaced.
4. Place the valve
measure the amount of stem runout with a
dial gauge. If it exceeds the maximum limit,
replace the valve.
Maximum valve stem runout:
0.01mm (0.0004 in)
on V-blocks, and
53