Cylinder Head Inspection - Yamaha SR125 1997 Service Manual

CYLINDER HEAD
5. Remove:
: Cylinder head
NOTE:
: Loosen the nuts in their proper loosening
sequence.
: Start by loosening each nut 1/2 turn until all
are loose.
YP402000

CYLINDER HEAD INSPECTION

1. Eliminate:
: Carbon deposits
(from combustion chambers)
Use a rounded scraper.
NOTE:
Do not use a sharp instrument to avoid
damaging or scratching:
: Spark plug threads
: Valve seats
2. Inspect:
: Cylinder head
Scratches/damage ! Replace.
3. Measure:
: Cylinder head warpage
Out of specification ! Resurface.
Cylinder head warpage:
Less than 0.03 mm
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Warpage measurement and resurfacement
steps:
: Place a straightedge and a feeler gauge
across the cylinder head.
: Measure the warpage.
If the warpage is out of specification, resurface
the cylinder head.
: Place a 400
the surface plate, and resurface the head us-
ing a figure-eight sanding pattern.
NOTE:
Rotate the cylinder head several times for an
even resurfacement.
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4-7
ENG
600 grit wet abrasive paper on