Checking The Camshaft Sprocket; Checking The Timing Chain Tensioner - Yamaha 2010 XMAX YP125R Service Manual

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.
Warpage limit
0.05 mm (0.0020 in)
M MMM M MMM M M MMM M
a. Place a straightedge "1" and a thickness
gauge "2" across the cylinder head.
1
b. Measure the warpage.
c. If the limit is exceeded, resurface the cylinder
head as follows.
d. Place 400–600 grit wet sandpaper on the sur-
face plate and resurface the cylinder head
using a figure-eight sanding pattern.
M MMM M M MMM M M MMM M
2
CYLINDER HEAD (YP250R)
TIP
To ensure an even surface, rotate the cylinder
head several times.
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EAS23870

CHECKING THE CAMSHAFT SPROCKET

1. Check:
• Camshaft sprocket
More than 1/4 tooth wear "a" → Replace the
camshaft sprocket, timing chain and crank-
shaft as a set.
a. 1/4 tooth
MMM
b. Correct
1. Timing chain roller
2. Camshaft sprocket
EAS24190

CHECKING THE TIMING CHAIN TENSIONER

1. Check:
• Timing chain tensioner
Cracks/damage → Replace.
2. Check:
• One-way cam operation
Rough movement → Replace the timing
chain tensioner housing.
3. Check:
• Cap bolt
• Spring
• One-way cam
• Timing chain tensioner rod
Damage/wear → Replace the defective
part(s).
5-70
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