Checking The Piston Pin - Yamaha FJR13AG Service Manual

2. Install:
• Piston ring
(into the cylinder)
TIP
Use the piston crown to level the piston ring near
bottom of cylinder "a", where cylinder wear is
lowest.
b. Top of cylinder
3. Measure:
• Piston ring end gap
Out of specification → Replace the piston
ring.
TIP
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 limit
0.55 mm (0.0217 in)
2nd ring
End gap limit
0.80 mm (0.0315 in)
EAS30749

CHECKING THE PISTON PIN

The following procedure applies to all of the pis-
ton pins.
CONNECTING RODS AND PISTONS
1. Check:
• Piston pin
2. Measure:
• Piston pin outside diameter "a"
a
3. Measure:
b
• Piston pin bore diameter "b"
4. Calculate:
• Piston-pin-to-piston-pin-bore clearance
• Piston-pin-to-piston-pin-bore clearance =
5-89
Blue discoloration/grooves → Replace the
piston pin and then check the lubrication sys-
tem.
Out of specification → Replace the piston pin.
Piston pin outside diameter
18.991–19.000 mm (0.7477–
0.7480 in)
Limit
18.971 mm (0.7469 in)
Out of specification → Replace the piston.
Piston pin bore inside diameter
19.004–19.015 mm (0.7482–
0.7486 in)
Limit
19.045 mm (0.7498 in)
Out of specification → Replace the piston pin
and piston as a set.
Piston pin bore diameter "b" -
Piston pin outside diameter "a"