Yamaha EH63 - Checking the Rocker Arms; Removing the Cylinder Heads; Checking the Cylinder Heads

CYLINDER HEAD COVERS, CYLINDER HEADS
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ENGINE
CHECKING THE ROCKER ARMS
1. Check:
• Rocker arm “1”
Wear/damage/cracks  Replace.
REMOVING THE CYLINDER HEADS
The following procedure applies to all of the cylinder
heads.
1. Remove:
• Cylinder head
TIP
Set the piston at TDC (top-dead-center) on the compres-
sion stroke.
(Refer to “ADJUSTING THE VALVE CLEARANCE” on
page 2-12.)
CHECKING THE CYLINDER HEADS
The following procedure applies to all of the cylinder
heads.
1. Check:
• Cylinder head combustion chamber
Check the combustion chamber for carbon depos-
its.
Carbon deposits  Eliminate.
TIP
Be sure not to damage the contact surface of the cylinder.
2. Check:
• Cylinder head
Cracks/damage around the hole of spark plug 
Replace.
3. Measure:
• Cylinder head warpage
TIP
Measure the warpage on the contact surface of the cylin-
der head at six points using the straight edge and thick-
ness gauge.
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