Yamaha Rhino 450 YXR45FAV, Service Manual, Page: 144 / 413

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ENG
CYLINDER HEAD
CHECKING THE CYLINDER HEAD
1. Eliminate:
• carbon deposits (from the combustion
chamber)
Use a rounded scraper.
NOTE:
Do not use a sharp instrument to avoid damag-
ing or scratching:
• Spark plug threads
• Valve seats
2. Check:
• cylinder head
Scratches/damage
→
Replace.
• cylinder head water jacket
Mineral deposits/rust
→
Eliminate.
3. Measure:
• cylinder head warpage
Out of specification
→
Resurface.
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a. Place a straightedge and a thickness gauge
across the cylinder head.
b. Use a thickness gauge to measure the
warpage.
c. If the warpage is out of specification, resur-
face the cylinder head.
d. Place a 400 ~ 600 grit wet sandpaper on
the surface plate, and resurface the head
using a figure-eight sanding pattern.
NOTE:
To ensure an even surface rotate the cylinder
head several times.
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Cylinder head warpage
Less than 0.03 mm (0.0012 in)