YAMAHA YZF-R1SC 2004 Service Manual

5-79
CONNECTING RODS AND PISTONSENG
NOTE:
NOTE:
EAS00387
REMOVING THE CRANKSHAFT ASSEMBLY
1. Remove:

crankshaft assembly

crankshaft journal upper bearings
(from the upper crankcase)
Refer to “CRANKSHAFT”.
Identify the position of each crankshaft journal
upper bearing so that it can be reinstalled in its
original place.
EAS00261
CHECKING THE CYLINDER AND PISTON
1. Check:

piston wall

cylinder wall
Vertical scratches
Replace the cylinder,
and the piston and piston rings as a set.
2. Measure:

piston-to-cylinder clearance
a. Measure cylinder bore “C” with the cylinder
bore gauge.
Measure cylinder bore “C” by taking side-to-
side and front-to-back measurements of the cyl-
inder. Then, find the average of the measure-
ments.
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5-80
CONNECTING RODS AND PISTONSENG
NOTE:Cylinder bore “C”
77.00
77.01 mm
(3.0315
3.0319 in)
Wear limit77.06 mm (3.03 in)
Taper limit “T”0.005 mm (0.0002 in)
Out of round “R”0.005 mm (0.0002 in)
“C” = maximum of D1
D6
“T” = maximum of D1 or D2 – maximum
of D
5 or D6
“R” = maximum of D1 D3 or D5 –
minimum of D
2 D4 or D6
b. If out of specification, replace the cylinder,
and the pistons and piston rings as a set.
c. Measure piston skirt diameter “P” with the
micrometer.
a4 mm (0.16 in) from the bottom edge of the piston
Piston size “P”
76.975
76.990 mm
(3.0305
3.0311 in)
d. If out of specification, replace the piston and
piston rings as a set.
e. Calculate the piston-to-cylinder clearance
with the following formula.
Piston-to-cylinder clearance =
Cylinder bore “C” –
Piston skirt diameter “P”
Piston-to-cylinder clearance
0.010
0.035 mm
(0.0004
0.0014 in)
: 0.120 mm (0.0047 in)
f. If out of specification, replace the cylinder,
and the piston and piston rings as a set.
EAS00263
CHECKING THE PISTON RINGS
1. Measure:

piston ring side clearance
Out of specification
Replace the piston
and piston rings as a set.
Before measuring the piston ring side clear-
ance, eliminate any carbon deposits from the
piston ring grooves and piston rings.
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5-81
CONNECTING RODS AND PISTONSENG
NOTE:
NOTE:
Piston ring side clearance
Top ring
0.030
0.065 mm
(0.0012
0.0026 in)
: 0.115 mm (0.0045 in)
2nd ring
0.020
0.055 mm
(0.0008
0.002 in)
: 0.115 mm (0.0045 in)
2. Install:

piston ring
(into the cylinder)
Level the piston ring into the cylinder with the
piston crown.
a5 mm (0.20 in)
3. Measure:

piston ring end gap
Out of specification
Replace the piston
ring.
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 end gap
Top ring
0.15
0.25 mm
(0.0059
0.0098 in)
: 0.50 mm (0.0197 in)
2nd ring
0.30
0.45 mm
(0.0118
0.0177 in)
: 0.80 mm (0.0315 in)
Oil ring
0.10
0.40 mm
(0.0039
0.0158 in)
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.
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5-82
CONNECTING RODS AND PISTONSENG
2. Measure:

piston pin outside diameter
a
Out of specification
Replace the piston
pin.
Piston pin outside diameter
16.991
17.000 mm
(0.6689
0.6693 in)
: 16.971 mm (0.6682 in)
3. Measure:

piston pin bore inside diameter
b
Out of specification
Replace the piston.
Piston pin bore inside diameter
17.002
17.013 mm
(0.6694
0.6698 in)
: 17.043 mm (0.6710 in)
4. Calculate:

piston-pin-to-piston clearance
Out of specification
Replace the piston pin
and piston as a set.
Piston-pin-to-piston clearance =
Piston pin bore size –
Piston pin outside diameter
Piston-pin-to-piston clearance
0.002
0.022 mm
(0.0001
0.0009 in)
: 0.072 mm (0.0028 in)
CHECKING THE BIG END BEARINGS
1. Measure:

crankshaft-pin-to-big-end-bearing clear-
ance
Out of specification
Replace the big end
bearings.
Crankshaft-pin-to-big-end-bearing
clearance
0.034
0.058 mm
(0.0013
0.0023 in)
: 0.09 mm (0.0035 in)
The following procedure applies to all of the
connecting rods.
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5-83
CAUTION:
CONNECTING RODS AND PISTONSENG
NOTE:
NOTE:
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 rods halves.
b. Install the big end upper bearing into the con-
necting rod and the big end lower bearing
into the connecting rod cap.
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.

Do not move the connecting rod or crankshaft
until the clearance measurement has been
completed.

Lubricate the bolt threads with molybdenum
disulfide grease.

Make sure that the “Y” mark
c on the connect-
ing rod faces towards the left side of the crank-
shaft.

Make sure that the characters
d on both the
connecting rod and connecting rod cap are
aligned.
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5-84
CONNECTING RODS AND PISTONSENG
NOTE:
NOTE:
NOTE:
CAUTION:
e. Tighten the connecting rod bolts.
Install by carrying out the following procedures
in order to assemble in the most suitable condi-
tion.
Connecting rod bolt
29.4 Nm (3.0 m
kg, 21 ft
lb)

First, tighten the bolts to 15 Nm (1.5 m
kg, 11
ft
lb).

Retighten the bolts to 29.4 Nm (3.0 m
kg, 21
ft
lb).
f. Replace the connecting rod bolts with new
ones.
g. Clean the connecting rod bolts.
h. After installing the big end bearing, assemble
the connecting rod and connecting rod cap
once using a single unit of the connecting
rod.
i. Tighten the connecting rod bolt while check-
ing that the sections shown
a and b are
flush with each other by touching the surface.

Side machined face
a

Thrusting faces (4 places at front and rear)
b
To install the big end bearing, care should be
taken not to install it at an angle and the position
should not be out of alignment.
j. Loosen the connecting rod bolt, remove the
connecting rod and connecting rod cap and
install these parts to the crankshaft with the
big end bearing kept in the current condition.
k. Tighten the connecting rod bolts.
Connecting rod bolt
20 Nm (2.0 m
kg, 14 ft
lb) + 150
Tighten the connecting rod bolts using the
plastic-region tightening angle method.
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5-85
CONNECTING RODS AND PISTONSENG
WARNING
CAUTION:
l. Clean the connecting rod bolts.
m. Tighten the connecting rod bolts.
n. Put a mark
1 on the corner of the connecting
rod bolt
2 and the connecting rod 3.
o. Tighten the bolt further to reach the specified
angle (150).
p. After the installation, check that the section
shown
a is flush with each other by touching
the surface.

Side machined face
a

When the bolt is tightened more than the
specified angle, do not loosen the bolt and
then retighten it.
Replace the bolt with a new one and per-
form the procedure again.

If they are not flush with each other, remove
the connecting rod bolt and big end bear-
ing and restart from step “e”. In this case,
make sure to replace the connecting rod
bolt.

Do not use a torque wrench to tighten the
nut to the specified angle.

Tighten the bolt until it is at the specified
angles.
q. Remove the connecting rod and big end
bearings.
Refer to “REMOVING THE CONNECTING
RODS”.
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5-86
CONNECTING RODS AND PISTONSENG
NOTE:
r. Measure the compressed Plastigauge
width on the crankshaft pin.
If the crankshaft-pin-to-big-end-bearing
clearance is out of specification, select re-
placement big end bearings.
2. Select:

big end bearings (P1
P4)

The numbers
A stamped into the crankshaft
web and the numbers
1 on the connecting
rods are used to determine the replacement
big end bearing sizes.

“P1”
“P4” refer to the bearings shown in the
crankshaft illustration.
For example, if the connecting rod “P
1” and the
crankshaft web “P
1” numbers are “5” and “2” re-
spectively, then the bearing size for “P1” is:
“P
1” (connecting rod) – “P1”
(crankshaft) =
5 – 2 = 3 (brown)
BIG END BEARING COLOR CODE
1Blue
2Black
3Brown
4Green
INSTALLING THE CONNECTING ROD AND
PISTON
The following procedure applies to all of the
connecting rods and pistons.
1. Install:

top ring
1

2nd ring 2

upper oil ring rail 3

oil ring expander 4

lower oil ring rail 5
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5-87
CONNECTING RODS AND PISTONSENG
NOTE:
NOTE:
Be sure to install the piston rings so that the
manufacturer’s marks or numbers
a face up.
2. Install:

piston
1
(onto the respective connecting rod 2)

piston pin
3

piston pin clip New 4

Apply engine oil onto the piston pin.

Make sure that the “Y” mark
a on the connect-
ing rod faces left when the arrow mark
b on
the piston is pointing up. Refer to the illustra-
tion.

Reinstall each piston into its original cylinder
(numbering order starting from the left: #1 to
#4).
3. Lubricate:

piston

piston rings

cylinder
(with the recommended lubricant)
Recommended lubricant
Engine oil
4. Offset:

piston ring end gaps
aTop ring
bLower oil ring rail
cUpper oil ring rail
d2nd ring
eOil ring expander
5. Lubricate:

crankshaft pins

big end bearings

connecting rod big end inner surface
(with the recommended lubricant)
Recommended lubricant
Engine oil
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5-88
CONNECTING RODS AND PISTONSENG
8 Nm (0.8 m
kg, 5.8 ft
lb)
NOTE:
NOTE:
29.4 Nm (3.0 m
kg, 21 ft
lb)
NOTE:
6. Check:

cylinder stud bolts
1
7. Install:

cylinder gasket
2 New
8. Install:

big end bearings
(onto the connecting rods and connecting
rod caps)

Align the projection
a on the big end bearings
with the notches
b in the connecting rods and
connecting rod caps.

Be sure to reinstall each big end bearing in its
original place.

Make sure that the characters
c on both the
connecting rod and connecting rod cap are
aligned.
9. Tighten:
Install by carrying out the following procedures
in order to assemble in the most suitable condi-
tion.

connecting rod bolts

First, tighten the bolts to 15 Nm (1.5 m
kg, 11
ft
lb).

Retighten the bolts to 29.4 Nm (3.0 m
kg, 21
ft
lb).
a. Replace the connecting rod bolts with new
ones.
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