Checking The Piston Pins; Installing The Pistons And Cylinders - Yamaha XV19SX(C) Service Manual

3. Measure:
• Piston ring end gap
Out of specification → Replace the piston
ring.
NOTE:
The oil ring expander spacer's end gap cannot
be measured. If the oil ring rail's gap is exces-
sive, replace all three piston rings.
Piston ring
Top ring
End gap (installed)
0.20–0.35 mm (0.0079–0.0138
in)
Limit
0.55 mm (0.0217 in)
2nd ring
End gap (installed)
0.45–0.60 mm (0.0177–0.0236
in)
Limit
0.95 mm (0.0374 in)
Oil ring
End gap (installed)
0.20–0.70 mm (0.0079–0.0276
in)
EAS24440

CHECKING THE PISTON PINS

The following procedure applies to all of the pis-
ton pins.
1. Check:
• Piston pin
Blue discoloration/grooves → Replace the
piston pin and then check the lubrication sys-
tem.
2. Measure:
• Piston pin outside diameter "a"
Out of specification → Replace the piston pin.
Piston pin outside diameter
22.991–23.000 mm (0.9052–
0.9055 in)
Limit
22.971 mm (0.9044 in)
CYLINDERS AND PISTONS
3. Measure:
• Piston pin bore diameter "b"
Out of specification → Replace the piston.
Piston pin bore inside diameter
23.004–23.015 mm (0.9057–
0.9061 in)
Limit
23.045 mm (0.9073 in)
4. Calculate:
• Piston-pin-to-piston-pin-bore clearance
Out of specification → Replace the piston pin
and piston as a set.
• Piston-pin-to-piston-pin-bore clearance =
Piston pin bore diameter "b" -
Piston pin outside diameter "a"
Piston-pin-to-piston-pin-bore
clearance
0.004–0.024 mm (0.00016–
0.00094 in)
EAS24460
INSTALLING THE PISTONS AND
CYLINDERS
The following procedure applies to all of the pis-
tons and cylinders.
1. Install:
• Top ring "1"
• 2nd ring "2"
• Lower oil ring rail "3"
• Upper oil ring rail "4"
• Oil ring expander "5"
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