Yamaha EF7000 Service Manual page 143

Check the valve clearance.
SUFFICIENT
Check the valve face and valve seat for wear.
GOOD
Check if there is seizure, wear, or damage on the
piston, piston ring, or cylinder.
GOOD
OUT OF
SPECIFICATION
WORN
SEIZURE OR WORN
6-8
TRBL
ENGINE
Adjust.
Resurface or replace.
Rebore or replace.