Removing The Pistons; Checking The Cylinders And Pistons - Yamaha 2012 TMAX XP500A Service Manual

EAS24380

REMOVING THE PISTONS

The following procedure applies to all of the
piston.
1. Remove:
• Piston pin clips "1"
• Piston pin "2"
• Piston "3"
ECA13810
Do not use a hammer to drive the piston
pin out.
TIP
• Before removing the piston pin clip, cover the
crankcase opening with a clean rag to pre-
vent the piston pin clip from falling into the
crankcase.
• For reference during installation, put an iden-
tification mark on each piston crown.
• Before removing the piston pin, deburr the
piston pin clip's groove and the piston's pin
bore area. If both areas are deburred and the
piston pin is still difficult to remove, remove it
with the piston pin puller set "4".
Piston pin puller set
90890-01304
Piston pin puller
YU-01304
CYLINDER AND PISTONS
2. Remove:
• Top ring
• 2nd ring
• Oil ring
TIP
When removing a piston ring, open the end
gap with your fingers and lift the other side of
the ring over the piston crown.
EAS24400

CHECKING THE CYLINDERS AND PISTONS

The following procedure applies to all of the
cylinders and pistons.
1. Check:
• Piston wall
• Cylinder wall
Vertical scratches → Replace the cylin-
der, piston and piston rings as a set.
2. Measure:
• Piston-to-cylinder clearance
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Measure cylinder bore with the cylinder
bore gauge.
TIP
Measure cylinder bore by taking side-to-side
and front-to-back measurements of the cylin-
der. Then, find the average of the measure-
ments.
Bore
68.000–68.010 mm (2.6772–
2.6776 in)
Wear limit
68.100 mm (2.6811 in)
Taper limit
0.050 mm (0.0020 in)
Out of round limit
0.050 mm (0.0020 in)
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