Yamaha TT-R125(W) Owner's Service Manual page 294

CYLINDER HEAD
4. Remove:
Bolt (camshaft sprocket) 1
G
Camshaft sprocket 2
G
NOTE:
Attach a wire a to the timing chain to prevent
it from falling into the crankcase.
5. Remove:
Bolts (cylinder head)
G
Cylinder head
G
NOTE:
Loosen the bolts 1/4 turn each and remove
G
then after all are loosened.
Loosen the bolts starting with the lowest
G
number one.
INSPECTION
Cylinder head
1. Eliminate:
Carbon deposits (from the combustion
G
chambers)
Use a rounded scraper.
NOTE:
Do not use a sharp instrument to avoid dam-
aging or scratching:
Spark plug threads
G
Valve seats
G
2. Inspect:
Cylinder head
G
Scratches/damage → Replace.
3. Inspect:
Cylinder head warpage
G
Out of specification → Re-surface.
Warpage measurement and re-surfacing
steps:
Attach a straightedge and a thickness
G
gauge on the cylinder head.
Measure the warpage.
G
4 - 15
ENG