Removing The Cylinder Head; Checking The Cylinder Head - Yamaha N MAX GPD150-A 2015 Service Manual

EAS30276

REMOVING THE CYLINDER HEAD

1. Align:
• "I" mark "a" on the AC magneto rotor
(with the match mark "b" on the right crank-
case)
▼ ▼▼▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼
a. Turn the crankshaft clockwise.
b. When the piston is at TDC on the compres-
sion stroke, align the "I" mark "c" on the cam-
shaft sprocket with the match mark "d" on the
camshaft stopper plate.
c
▲ ▲▲▲ ▲ ▲▲▲ ▲ ▲ ▲▲▲ ▲
2. Loosen:
• Camshaft sprocket bolt "1"
TIP
Use the camshaft wrench "2" and loosen the
camshaft sprocket bolt.
Camshaft wrench
90890-04162
Camshaft wrench
YM-04162
2
▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼
d
▲ ▲▲▲ ▲ ▲ ▲▲▲ ▲ ▲ ▲▲▲ ▲
1
3. Remove:
• Cylinder head
TIP
• Loosen the bolts and nuts in the proper se-
quence as shown.
• Loosen each bolt and nuts 1/2 of a turn at a
▼▼▼
time. After all of the bolts and nuts are fully
loosened, remove them.
b
a
EAS30277

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.
• Cylinder head water jacket
Mineral deposits/rust → Eliminate.
3. Measure:
• Cylinder head warpage
Out of specification → Resurface the cylinder
head.
5-13
CYLINDER HEAD
4
6
1
Warpage limit
0.05 mm (0.0020 in)
×
3
4
×
2
5
2