1999 YAMAHA YZF-R7 Owners Manual

4 - 69
ENGCONNECTING RODS AND PISTONS
c. Put a piece of Plastigaugeâ 1 on the
crankshaft pin.
d. Assemble the connecting rod halves.
NOTE:
• Do not move the connecting rod or
crankshaft until the clearance mea-
surement has been completed.
• Lubricate the bolt threads and nut
seats with MOLYKOTE
® G-n paste.
• Make sure that the “Y” mark c on the
connecting rod faces towards the left
side of the crankshaft.
• Make sure that the characters d on
both the connecting rod and connect-
ing rod cap are aligned.
e. Tighten the connecting rod nuts.
Refer to “INSTALLING THE PISTONS
AND CONNECTING RODS”.
f. Remove the connecting rod and big
end bearings.
Refer to “REMOVING THE CONNECT-
ING RODS AND PISTONS”.
g. Measure the compressed Plasti-
gauge
â width e on the crankshaft
pin.
If the crankshaft pin-to-big end bear-
ing clearance is out of specification,
select replacement big end bearings.
s s s s s s s s s s s s s s s s s s s s s s s s s s s

4 - 70
ENGCONNECTING RODS AND PISTONS
2. Select:
• big end bearings (“P
1”~ “P4”)
NOTE:
• The numbers stamped into the crank-
shaft web and the numbers on the
connecting rods are used to determine
the replacement big end bearing sizes.
•“P
1”~“P4” refer to the bearings shown
in the crankshaft illustration.
t t t t t t t t t t t t t t t t t t t t t t t t t t t
For example, if the connecting rod
“P
1” and the crankshaft web “P1” num-
bers are “9” and “3” respectively, then
the bearing size for “P
1” is:
s s s s s s s s s s s s s s s s s s s s s s s s s s s
“P1” (connecting rod) – “P1” (crank-
shaft) =
9 – 3 = 6
BIG END BEARING COLOR CODE
2 blue
3
black
4
5
brown
6
7
green
8
9 yellow
EB404704
INSTALLING THE PISTONS AND
CONNECTING RODS
The following procedure applies to all of
the pistons and cylinders.
1. Install:
• top ring
• 2nd ring
• oil ring
NOTE:
Be sure to install the piston rings so that
the manufacturer’s marks or numbers
face up.

4 - 71
ENGCONNECTING RODS AND PISTONS
2. Install:
• piston 1
(onto the respective connecting rod 2)
• piston pin 3
• piston pin clip 4
NOTE:
• Apply engine oil onto the piston pin.
• Make sure that the “Y” mark a on the
connecting rod faces left when the
arrow mark b on the piston is pointing
up. Refer to the illustration.
• Reinstall each piston into its original
cylinder (numbering order starting
from the left: #1 to #4).
Piston head
New
3. Offset:
• piston ring end gaps
aTop ring
bLower oil ring rail
cUpper oil ring rail
d2nd ring
Intake side
4. Lubricate:
• piston
• piston rings
• cylinder
(with the recommended lubricant)
5. Lubricate:
• bolt threads
• nut seats
(with the recommended lubricant)
ACHTUNG:CAUTION:
MOLYKOTEâ “G-n” paste is a special
grease, which should not be applied to
any part other than those specified.
Recommended lubricant
Engine oil
Recommended lubricant
MOLYKOTE® G-n paste

4 - 72
ENGCONNECTING RODS AND PISTONS
NOTE:
Apply only a thin even layer of
MOLYKOTE‚ “G-n” paste, otherwise the
correct tightening torque cannot be
achieved.
6. Lubricate:
• crankshaft pins
• big end bearings
• connecting rod big end inner surface
(with the recommended lubricant)
Recommended lubricant
Engine oil
7. Install:
• big end bearings
• connecting rod assembly
(into the cylinder and onto the crank-
shaft pin)
• connecting rod cap
(onto the connecting rod)
NOTE:
• Align the projections on the big end
bearings with the notches in the con-
necting rods and connecting rod caps.
• Be sure to reinstall each big end bear-
ing in its original place.
• While compressing the piston rings
with piston ring compressor 1, install
the connecting rod assembly into the
cylinder with the other hand.
• Make sure that the “Y” marks a on the
connecting rods face towards the left
side of the crankshaft.
• Make sure that the characters b on
both the connecting rod and connect-
ing rod cap are aligned.
8. Align:
• bolt heads
(with the connecting rods)
Piston ring compressor:
90890-05158
1

4 - 73
ENGCONNECTING RODS AND PISTONS
9. Tighten:
• connecting rod nuts
t t t t t t t t t t t t t t t t t t t t t t t t t t t
• Tighten the connecting rod nuts in the
following way.
NOTE:
• How much the connecting rod nut is
tightened depends on how much the
connecting rod bolt stretches.
• Use a general micrometer 1 to mea-
sure the connecting rod bolts.
a. Before tightening the connecting rod
nut, measure the length of the con-
necting rod bolt with an accuracy of
three decimal places.
b. First tighten the connecting rod nut to
20 Nm (2.0 m • kg, 14 ft • lb), then up
to 40 Nm (4.0 m • kg, 29 ft • lb).
c. Measure the length of the connecting
rod bolt after tightening the connect-
ing rod nut and then calculate how
much the bolt has stretched.
d. Further tighten the connecting rod
nut until the connecting rod bolt has
stretched by between 0.170 and
0.175 mm.
ACHTUNG:CAUTION:
If the connecting rod nut cannot eventu-
ally be tightened to about 50 Nm (5.0 m
• kg, 36 ft • lb), too much MOLYKOTE
®‚
“G-n” paste may have been applied.
Loosen the connecting rod nut and
check the loosening torque. If the loos-
ening torque is less than 40 Nm (4.0 m •
kg, 29 ft • lb), too much MOLYKOTE
®‚
“G-n” paste was applied. In that case,
replace the connecting rod bolt with a
new one and apply a thin uniform layer
of MOLYKOTE
®‚ “G-n” paste to the
threads of the connecting rod bolt, the
contact area between the connecting
rod and the connecting rod bolt, and the
seat of the connnecting rod nut. Then,
tighten the connecting rod nut as
explained above.
WARNINGWARNING
Always replace the connecting rod bolt
with a new one if loosening the con-
necting rod nut after it was tightened.
Never use a connecting rod bolt more
than once.
s s s s s s s s s s s s s s s s s s s s s s s s s s s
0.17 0
1

ENG
4 - 74
CRANKSHAFT
EB412000
CRANKSHAFT
Order Job/Part Q’ty Remarks
Removing the crankshaft assemblyRemove the parts in the order listed.
Crankcase Separate.
Refer to “CRANKCASE”.
Connecting rod caps Refer to “CONNECTING RODS AND
PISTONS”.
1 Crankshaft 1
2 Crankshaft journal lower bearing 5
3 Crankshaft journal upper bearing 5
For installation, reverse the removal
procedure.

4 - 75
ENGCRANKSHAFT
EB412110
REMOVING THE CRANKSHAFT
1. Remove:
• crankshaft 1
• crankshaft journal upper bearings
(from the upper crankcase)
NOTE:
Identify the position of each crankshaft
journal upper bearing so that it can be
reinstalled in its original place.
EB412403
CHECKING THE CRANKSHAFT
1. Measure:
• crankshaft runout
Out of specification ® Replace the
crankshaft.
Maximum crankshaft runout
0.035 mm (0.0014 in)
2. Check:
• crankshaft journal surfaces
• crankshaft pin surfaces
• bearing surfaces
Scratches/wear ® Replace the crank-
shaft.
CHECKING THE CRANKSHAFT JOURNAL
BEARINGS
1. Measure:
• crankshaft journal-to-crankshaft jour-
nal bearing clearance
Out of specification ® Replace the
crankshaft journal bearings.
t t t t t t t t t t t t t t t t t t t t t t t t t t t
ACHTUNG:CAUTION:
Do not interchange the crankshaft jour-
nal bearings. To obtain the correct
crankshaft journal-to-crankshaft journal
bearing clearance and prevent engine
damage, the crankshaft journal bearings
must be installed in their original posi-
tions.
Crankshaft journal-to-crank-
shaft journal bearing clearance
0.036 ~ 0.056 mm
(0.0014 ~ 0.0022 in)

4 - 76
ENGCRANKSHAFT
a. Clean the crankshaft journal bearings,
crankshaft journals, and bearing por-
tions of the crankcase.
b. Place the upper crankcase upside
down on a bench.
c. Install the crankshaft journal upper
bearings 1 and the crankshaft into
the upper crankcase.
NOTE:
Align the projections a on the crank-
shaft journal upper bearings with the
notches b in the upper crankcase.
d. Put a piece of Plastigauge
Ò 2 on each
crankshaft journal.
NOTE:
Do not put the PlastigaugeÒ over the oil
hole in the crankshaft journal.
e. Install the crankshaft journal lower
bearings into the lower crankcase and
assemble the crankcase.
NOTE:
• Align the projections a on the crank-
shaft journal lower bearings with the
notches b in the lower crankcase.
• Do not move the crankshaft until the
clearance measurement has been
completed.
f. Tighten the bolts to specification in
the tightening sequence cast on the
crankcase.
NOTE:
Lubricate the crankcase bolt threads
with engine oil.
T R..
Bolt 1 ~ @
32 Nm (3.2 m • kg, 23 ft • lb)
Bolt A ~ E, G ~ J, M, O ~ R
12 Nm (1.2 m • kg, 8.7 ft • lb)
Bolt F, N
14 Nm (1.4 m • kg, 10 ft • lb)
Bolt K, L
24 Nm (2.4 m • kg, 17 ft • lb)