Checking The Cylinder Heads - Yamaha XVS250 2001 Service Manual

CYLINDER HEADS
EAS00228

CHECKING THE CYLINDER HEADS

The following procedure applies to all of the cyl-
inder heads.
1. Eliminate:
D combustion chamber carbon deposits
(with a rounded scraper)
NOTE:
Do not use a sharp instrument to avoid damag-
ing or scratching:
D spark plug threads
D valve seats
2. Check:
D cylinder head
Damage/scratches  Replace.
3. Measure:
D cylinder head warpage
Out of specification  Resurface the cylin-
der head.
Cylinder head warpage
Less than 0.03 mm
a. Place a straightedge 1 and a thickness
gauge 2 across the cylinder head.
b. Measure the warpage.
c. If the limited is exceeded, resurface the cylin-
der head as follows.
d. Place 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.
5-10
ENG