Yamaha YZF-R1 2015, Service Manual

Page: 416 / 704

CONNECTING RODS AND PISTONS
5-75
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.
3. Measure:
•
Piston ring end gap
Out of specification
o
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.
EAS30749
CHECKING THE PISTON PIN
The following procedure applies to all of the pis-
ton pins.
1. Measure:
•
Piston pin outside diameter “a”
Out of specification
o
Replace the piston pin.
2. Measure:
• Piston pin bore inside diameter “b”
Out of specification
o
Replace the piston.
3. Calculate:
•
Piston-pin-to-piston-pin-bore clearance
Out of specification
o
Replace the piston pin
and piston as a set.
Top ring
End gap (installed)
0.15–0.25 mm (0.0059–0.0098 in)
Limit
0.50 mm (0.0197 in)
2nd ring
End gap (installed)
0.65–0.80 mm (0.0256–0.0315 in)
Limit
1.15 mm (0.0453 in)
Oil ring
End gap (installed)
0.10–0.35 mm (0.0039–0.0138 in)
b. Upper of cylinder
a
b
Piston pin outside diameter
16.991–17.000 mm (0.6689–
0.6693 in)
Limit
16.971 mm (0.6681 in)
Piston pin bore inside diameter
17.002–17.013 mm (0.6694–
0.6698 in)
Limit
17.043 mm (0.6710 in)
Piston-pin-to-piston-pin-bore clearance = Piston
pin bore inside diameter “b” - Piston pin outside
diameter “a”