Removing The Cylinder Head; Checking The Cylinder Head - Yamaha RAPTOR YFM125RA Service Manual

EAS24130

REMOVING THE CYLINDER HEAD

1. Align:
• "I" mark "a" on the generator rotor
(with the stationary pointer "b" on the
generator rotor cover)
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a. Turn the crankshaft counterclockwise.
b. When the piston is at TDC on the compres-
sion stroke, align the "I" mark "c" on the
camshaft sprocket with the mark "d" on the
cylinder head.
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2. Loosen:
• Camshaft sprocket bolt "1"
TIP
While holding the generator rotor nut with a
wrench, remove the bolt.
3. Loosen:
• Timing chain tensioner cap bolt
4. Remove:
• Timing chain tensioner
(along with the gasket)
• Camshaft sprocket
• Timing chain
TIP
To prevent the timing chain from falling into the
crankcase, fasten it with a wire.
5. Remove:
• Cylinder head
TIP
• Loosen the bolts in the proper sequence as
shown.
• Loosen each nut 1/2 of a turn at a time. After
all of the bolts are fully loosened, remove
them.
EAS24160

CHECKING THE CYLINDER HEAD

1. Eliminate:
• Combustion chamber carbon deposits
(with a rounded scraper)
TIP
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.
5-8
CYLINDER HEAD