Checking The Cylinder Head - Yamaha XC50V Service Manual

CYLINDER HEAD
EAS00227

CHECKING THE CYLINDER HEAD

1. Eliminate:
8 combustion chamber carbon deposits
(with a rounded scraper)
NOTE:
Do not use a sharp instrument to avoid damag-
ing or scratching:
8 spark plug bore thread
8 valve seats
2. Check:
8 cylinder head
Damage/scratches
3. Measure:
8 cylinder head warpage
Out of specification
inder head.
Maximum cylinder head warpage
0.03 mm (0.001 in)
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a. Place a straightedge and a thickness gauge
across the cylinder head.
b. Measure the warpage.
c. If the limit is exceeded, resurface the cylin-
der head as follows.
d. Place a 400 ~ 600 grit wet sandpaper on
the surface plate and resurface the cylin-
der head using a figure-eight sanding pat-
tern.
NOTE:
To ensure an even surface, rotate the cylinder
head several times.
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5-8
ENG
Replace.
Resurface the cyl-