Yamaha Fz1n Service Manual

CRANKSHAFT
5-73
NOTE:
Identify the position of each crankshaft journal 
upper bearing so that it can be reinstalled in its 
original place.
ET2D1032
CHECKING THE CYLINDER AND PISTON
1. Check: Piston wall
 Cylinder wallVertical scratches  → Replace the cylinder, 
and the piston and piston rings as a set.
2. Measure:
 Piston-to-cylinder clearance
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a. Measure cylinder bore “C” with the cylinder  bore gauge.
NOTE:
Measure cylinder bore “C” by taking side-to-
side and...

CRANKSHAFT
5-74
2. Install: Piston ring(into the cylinder)
NOTE:
Level the piston ring into the cylinder with the 
piston crown.
5 mm (0.20 in) “a”
3. Measure:  Piston ring end gapOut of specification  → Replace the piston 
ring.
NOTE:
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.
ET2D1016
CHECKING THE PISTON PINS
The following procedure applies to all of the 
piston pins.
1. Check:  Piston pinBlue...

CRANKSHAFT
5-75
4. Calculate: Piston-pin-to-position clearanceOut of specification  → Replace the position 
pin and piston as a set.
ET2D1017
CHECKING THE BIG END BEARINGS
1. Measure:  Crankshaft-pin-to-big-end-bearing crear-
ance
Out of specification  → Replace the big end 
bearings.
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The following procedure applies to all of the 
connecting rods.
CAUTION:
ECA14900
Do not interchange the big end bearings 
and connecting rods. To obtain the correct...

CRANKSHAFT
5-76
e. Tighten the connecting rod bolts.
NOTE:
Install by carrying out the following procedures 
in order to assemble in the most suitable con-
dition.
NOTE:
 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 big end bearing, assemble  the connecting rod and connecting rod cap 
once using a single unit of the connecting...

CRANKSHAFT
5-77
p. After the installation, check that the section shown “a” is flush with each other by touch-
ing the surface.
 Side machined face “a”
WARNING
EWA13120
 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 bearing and restart from step “e”. In 
this case, make sure to replace the...

CRANKSHAFT
5-78
EAS26190
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”
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 “4”  
NOTE:
 Apply engine oil onto the piston...

CRANKSHAFT
5-79
8. Install: Big end bearings(onto the connecting rods and connecting 
rod caps)
NOTE:
 Align the projections “a” on the big end bear-ings 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” a on both  the connecting rod and connecting rod cap 
are aligned.
9. Tighten:  Connecting rod bolts
NOTE:
 Install by carrying out the following proce-
dures in order to...

CRANKSHAFT
5-80
11. Install: Cylinder assembly “1”
 Connecting rod caps “2”
NOTE:
 Make sure that the “Y” marks “a” on the con-necting rods face towards the left side of the 
crankshaft.
 Make sure that the characters on both the  connecting rod and connecting rod cap are 
aligned.
12. Tighten:  Connecting rod bolts
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CAUTION:
ECA14980
Tighten the connecting rod bolts using the 
plastic-region tightening angle method.
a. Clean the connecting rod bolts.
b. Tighten the...

CRANKSHAFT
5-81
 If they are not flush with each other, remove the connecting rod bolt and big 
end bearing and restart from step “9”. In 
this case, make sure to replace the con-
necting rod bolt.
CAUTION:
ECA14680
 Do not use a torque wrench to tighten the 
bolt to the specified angle.
 Tighten the bolt until it is at the specified 
angles.
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ET2D1018
CHECKING THE CRANKSHAFT
1. Measure:  Crankshaft runout
Out of specification  → Replace the crank-
shaft.
2. Check: ...

CRANKSHAFT
5-82
d. Put a piece of Plastigauge® “2” on each crankshaft journal.
NOTE:
Do not put the Plastigauge® over the oil hole in 
the crankshaft journal.
e. Install the crankshaft journal lower bear-ings “1” into the lower crankcase and 
assemble the crankcase halves.
NOTE:
 Align the projections “a” of the crankshaft 
journal lower bearings with the notches “b” in 
the lower crankcase.
 Do not move the crankshaft until the clear-
ance measurement has been completed.
f. Tighten the bolts to...