Yamaha YZF-R25, Service Manual

Page: 299 / 456

CRANKSHAFT AND BALANCER SHAFT
5-82
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The following procedure applies to both of the
connecting rods.
NOTICE
ECA13930
Do not interchange the big end bearings and
connecting rods. To obtain the correct
crankshaft-pin-to-big-end-bearing clear-
ance and prevent engine damage, the big
end bearings must be installed in their origi-
nal positions.
a. Clean the big end bearings, crankshaft pins,
and the inside of the connecting rod halves.
b. Install the big end upper bearing into the con-
necting rod and the big end lower bearing into
the connecting rod cap.
TIP
Align the projections “a” on the big end bearings
with the notches “b” in the connecting rod and
connecting rod cap.
c. Put a piece of Plastigauge® “1” on the crank-
shaft pin.
d. Assemble the connecting rod halves.
TIP
• Do not move the connecting rod or crankshaft
until the clearance measurement has been
completed.
• Lubricate the bolt threads and nut seats with
molybdenum disulfide oil.
• Make sure the “Y” mark “c” on the connecting
rod faces towards the left side of the crank-
shaft.
• Make sure the characters “d” on both the con-
necting rod and connecting rod cap are
aligned.
• Make sure that the projections “e” on the con-
necting rod cap faces the same direction as the
“Y” mark “c” on the connecting rod.
e. Tighten the connecting rod nuts.
Refer to “INSTALLING THE CONNECTING
RODS” on page 5-83.
f. Remove the connecting rod and big end
bearings.
Refer to “REMOVING THE CONNECTING
RODS” on page 5-78.
g. Measure the compressed Plastigauge®
width “f” on the crankshaft pin.
If the crankshaft-pin-to-big-end-bearing
clearance is out of specification, select re-
placement big end bearings.
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2. Select:
• Big end bearings (P
1
–P
2
)
TIP
• The numbers “A” stamped into the crankshaft
web and the numbers “B” on the connecting
rods are used to determine the replacement
big end bearing sizes.
• P
1
–P
2
refer to the bearings shown in the crank-
shaft illustration.
1
e
d
c
f