Yamaha FX Nytro 2008 Manuel D'atelier page 436

5 9 7
4 8 10
2
1
CYLINDER HEAD
REMOVAL
1. Remove:
• Cylinder head bolts
3
1
NOTE:
• Loosen the bolts in the proper sequence as
shown.
2
• Loosen each bolt 1/2 of a turn at a time. After all
of the bolts are fully loosened, remove them.
6
INSPECTION
1. Eliminate:
• Combustion chamber carbon deposits
NOTE:
Do not use a sharp instrument to avoid damaging
or scratching:
• Spark plug bore threads
• Valve seats
2. Check:
• Cylinder head
• Cylinder head water jacket
3. Measure:
• Cylinder head warpage
Measurement steps:
• Place a straightedge 1 and a thickness gauge
2 across the cylinder head.
• Measure the warpage.
• If the limit is exceeded, resurface the cylinder
head as follows.
• Place a 400 ~ 600 grit wet sandpaper on the
surface plate and resurface the cylinder head
using a figure-eight sanding pattern.
NOTE:
To ensure an even surface, rotate the cylinder head
several times.
5-27
ENG
(with a rounded scraper)
Damage/scratches → Replace.
Mineral deposits/rust → Eliminate.
Out of specification → Resurface the cylinder
head.
Maximum cylinder head warpage:
0.10 mm (0.0039 in)