Yamaha XSR900 2022, Service Manual

Page: 245 / 726

5-28
CYLINDER HEAD
EAS30276
REMOVING THE CYLINDER HEAD
1. Remove:
• Intake camshaft
• Exhaust camshaft
Refer to “REMOVING THE CAMSHAFTS”
on page 5-20.
2. Remove:
• Cylinder head bolt (M6) (
×
4)
• Cylinder head bolt (M9) (
×
8)
TIP
• Loosen the bolts in the proper sequence as
shown.
• Loosen each bolt 1/2 of a turn at a time. After
all of the bolts are fully loosened, remove them.
EAS30278
CHECKING THE TIMING CHAIN GUIDE
(EXHAUST SIDE)
1. Check:
• Timing chain guide (exhaust side)
Damage/wear
→
Replace.
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.
a. Place a straightedge “1” and a thickness
gauge “2” across the cylinder head.
b. Measure the warpage.
c. If the limit is exceeded, resurface the cylin-
der head as follows.
d. Place a 400–600 grit wet sandpaper on the
surface plate and resurface the cylinder
head using a figure-eight sanding pattern.
TIP
To ensure an even surface, rotate the cylinder
head several times.
8
1
2
3
4
5
6
7
8
9
10
11
12
4
Warpage limit
0.10 mm (0.00 3 9 in)
Thickness gauge
90890-0 3 268
Feeler gauge set
YU-26900-9
G088955
2
1
G088957