5 - 8
ENG
EAS00229
CHECKING THE CYLINDER HEAD
1. Eliminate:
• combustion chamber carbon deposits
(with a rounded scraper)
NOTE:
Do not use a sharp instrument to avoid damag-
ing or scratching:
• spark plug bore threads
• valve seats
2. Check:
• cylinder head
Damage/scratches
→
Replace.
• cylinder head water jacket
Mineral deposits/rust
→
Eliminate.
3. Measure:
• cylinder head warpage
Out of specification
→
Resurface the cylin-
der head.
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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 cylinder
head using a figure-eight sanding pattern.
NOTE:
To ensure an even surface, rotate the cylinder
head several times.
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Maximum cylinder head warpage
0.05 mm (0.0020 in)
Summary of Contents for YP250R 2005
Page 1: ...YP250R SERVICE MANUAL 2005 1C0 F8197 E0 ...
Page 368: ...YAMAHA MOTOR ESPAÑA S A ...