3-33.2. EXHAUST VALVE - MAINTENANCE INSTRUCTIONS (Cont).
Remove and discard the valve guide
oil seals if used. Clean the in-
side diameter of the valve guides
with a brush. This brush will re-
move all gum or carbon deposits
from the guides, including the
spiral grooves. Inspect the valve
guides for fractures, chipping,
scoring, or excessive wear. Check
the valve-to-guide clearance, since
worn valve guides may eventually
result in improper valve seat contact.
If the clearance exceeds .005 inch
(0.0127 cm), replace the valve guides.
Inspect the valve seat inserts for
excessive wear, pitting, cracking
or an improper seat angle. The
proper angle for the seating face
of both the valve and insert is 30
When a valve seat insert has been
ground to such an extent that the
30angle will contact the cylin-
der head, install a new insert.