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

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.
Warpage limit
0.05 mm (0.0020 in)
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a. Place a straightedge "1" and a thickness
gauge "2" across the cylinder head.
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b. Measure the warpage.
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CYLINDER HEAD (YP125R)
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.
TIP
To ensure an even surface, rotate the cylinder
head several times.
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EAS37P1004

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
b. Correct
MMM
1. Timing chain roller
2. Camshaft sprocket
EAS37P1005

CHECKING THE TIMING CHAIN TENSIONER

1. Check:
• Timing chain tensioner
Cracks/damage → Replace.
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a. Remove the timing chain tensioner plug.
b. While lightly pressing the timing chain ten-
sioner rod by hand, turn the tensioner rod ful-
ly clockwise with a thin screwdriver "1".
c. Remove the screwdriver and slowly release
the timing chain tensioner rod.
5-10
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