Cylinder Head Inspection - Yamaha Scorpio Service Manual

CYLINDER HEAD
12.Remove:
Dowel pins 1
G
Gasket (cylinder head) 2
G
Timing chain guide (exhaust side) 3
G

CYLINDER HEAD INSPECTION

1.Eliminate:
Carbon deposits
G
(from combustion chambers)
Use a rounded scraper.
NOTE:
Do not use a sharp instrument to avoid damag-
ing or scratching:
Spark plug threads
G
Valve seats
G
2.Inspect:
Cylinder head
G
Scratches/damage → Replace.
3.Measure:
Cylinder head warpage
G
Out of specification → Resurface.
Cylinder head warpage:
Less than 0.03 mm
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Warpage measurement and resurfacement
steps:
G
Place a straightedge and feeler gauge
across the cylinder head.
G
Measure the warpage.
G
If the warpage is out of specification, resur-
face the cylinder head.
G
Place a 400 ~ 600 grit wet abrasive paper on
the surface plate, and resurface the head
using a figure-eight sanding pattern.
NOTE:
Rotate the cylinder head several times for an
even resurfacement.
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ENG