Yamaha EF1000iS Service Manual

							ENG
3-22
CRANKSHAFT, PISTON AND PISTON RING
EE
E
E
1 2 34 5
67
8 46 Nm (0.6 m · kg, 4.3 ft · lb)
Order Job name Q’ty Remarks
4 Piston pin circlip 2
5 Piston pin 1
6 Connecting rod 1
7 Piston ring set 1
8 Piston 1
For installation, reverse the removal
procedure.
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							3-23
CRANKSHAFT, PISTON AND PISTON RING
P
aPISTON AND PISTON PIN INSPECTION
1. Measure:
9Piston skirt diameter P
a= 10 mm (0.4 in) from the piston bottom
edge
Out of specification →Replace.
2. Measure:
9Piston clearance
Out of specifications →Rebore or
replace cylinder and replace piston and
piston rings.
3. Measure:
9Piston pin hole inside diameter a
Out of specifications →Replace.
ENG
Piston skirt diameter:
Standard:
40.95 ~ 40.97 mm
(1.612 ~ 1.613 in)
Piston pin hole inside diameter:
Standard:
10.000 ~ 10.020 mm
(0.3937 ~ 0.3945 in)
Limit:
10.050 mm
(0.3956 in)
Piston clearance:
0.01 ~ 0.04 mm
(0.0004 ~ 0.0016 in)
Piston clearance =
Cylinder inside diameter - 
Piston skirt diameter
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							3-24
CRANKSHAFT, PISTON AND PISTON RING
a
a1
4. Measure:
9Piston pin diameter a
Out of specifications →Replace.
5. Inspect:
9Check the piston pin enters smoothly
into the piston pin hole.
If the piston pin fits tightly into the pis-
ton, check the piston pin hole. If there is
any protrusion, use a knife or scraper to
gently remove it so that piston pin can
be pushed in gently with your fingers.
PISTON RING INSPECTION
1. Measure:
9Piston ring end gap
Out of specification →Replace.
NOTE:
Insert the piston ring 1into the cylinder, and
push it approximately a5 mm (0.2 in) into the
cylinder. Push the ring with the piston crown
so that the ring is at angles to the cylinder
bore.
Out of specifications →Replace the
piston and piston ring as a set.
ENG
Piston pin diameter:
9.99 ~ 10.00 mm
(0.3933 ~ 0.3937 in)
Limit:
9.95 mm
(0.3917 in)
Top ringWear limit Ring end gap
0.6 mm
(0.0236 in) 0.10 ~ 0.30 mm
(0.0039 ~ 0.0118in)
2nd ring0.6 mm
(0.0236 in) 0.10 ~ 0.30 mm
(
0.0039 ~ 0.0118in)
Oil ring0.9 mm
(0.0354 in) 0.2 ~ 0.7 mm
(0.0078 ~ 00275 in)
7VV10-03  02.10.4 10:39 AM  Page 24 
						

							3-25
CRANKSHAFT, PISTON AND PISTON RING
1
1
a
2. Measure:
9Piston side clearance
Out of specification →Replace.
NOTE:
9Clean carbon deposits from the piston ring
grooves and ring s before measuring the
side clearance.
9Measure the side clearance at several por-
tions.
CRANKSHAFT INSPECTION
1. Measure:
9Crankshaft runout limit
use a dial gauge
Out of specification →Replace.
2. Inspect:
9Crankshaft sprocket 1
Crack/damage/wear →Replace the
crankshaft.
3. Measure:
9Crank pin diameter a
Out of specification →Replace the
crankshaft.
ENG
Top ringWear limit Piston ring side
clearance
0.15 mm
(0.006 in) 0.06 ~ 0.11 mm
(0.002 ~ 0.004 in)
2nd ring0.06 ~ 0.11 mm
(0.002 ~ 0.004 in)
Runout limit:
0.03 mm (0.001 in)
Crank pin diameter:
15.970 ~ 15.985 mm
(0.629 ~ 0.630 in)
Limit:
15.940 mm
(0.627 in)
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							3-26
CRANKSHAFT, PISTON AND PISTON RING
1
1
2
CONNECTING ROD OIL CLEARANCE
INSPECTION
NOTE:
Measure the oil clearance if replacing the
crankshaft or connecting rod.
1. Place a piece of Plastigauge 1on the
crank pin horizontally.
NOTE:
Clean off oil from all parts thoroughly.
2. Install:
9Connecting rod 1
9Connecting rod cap 1
NOTE:
Tighten the cap bolts so that the crankshaft
does not move while the oil clearance is being
measured.
3. Remove:
9Connecting rod cap
9Connecting rod
4. Measure:
9Connecting rod oil clearance
Widest portion of the pressed
Plastigauge
Out of specification →Replace crank-
shaft or connecting rod, and then mea-
sure the clearance again.
ENG
Connecting rod oil clearance:
0.015 ~ 0.050 mm
(0.0006 ~ 0.0020 in)
Limit:
0.100 mm
(0.004 in)
6 Nm (0.6 m · kg, 4.3 ft · lb)
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							3-27
CRANKSHAFT, PISTON AND PISTON RING
1
2
3
1
2
3
RN
a
b
1
2 3
120°
120° 120°Top ring
Second ringOil ring
a
1
2
PISTON AND PISTON RING INSTALLATION
1. Install:
9Top ring
9Second ring
9Oil ring ring
NOTE:
9Be sure to install the top ring and second
ring so that the “RN” mark a faces towerd
the piston head.
9Make sure that the piston rings move
smoothly.
2. Apply 4-stroke engine oil to the inside of
the connecting rod small end.
3. Install:
9Piston 1
9Piston pin 2
9Piston pin circlip 3 
NOTE:
Make sure that the “YAMAHA” mark aon the
piston head and the “7VV” mark bon the con-
necting rod toward as same faces, then install.
CONNECTING ROD AND CRANKSHAFT
INSTALLATION
1. Make sure that the end gap of each piston
ring is positioned, as shown in the illustra-
tion.
2. Install:
9Piston 1
9Connecting rod 2
cC
Make sure that the “7VV” mark aon the con-
necting rod faces toward the crankcase cover.
ENG
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							3-28
CRANKSHAFT, PISTON AND PISTON RING
a
b
1 2
3. Install:
9Crankshaft 1
9Connecting rod cap 2
cC
Make sure that the “∇” mark aon the con-
necting rod is aligned the “∆” mark bon the
rod cap.
4. Install:
9Crankshaft
9Connecting rod cap
9Cam follower (exhaust side)
9Cam follower (intake side)
9Collar
9Push rod
9Rocker arm
9Crankcase 2
Refer to “CRANKCASE 2 AND
CAMSHAFT” section.
ENG
6 Nm (0.6 m · kg, 4.3 ft · lb)
8 Nm (0.8 m · kg, 5.8 ft · lb)
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							ENG
3-29
CYLINDER (CRANKCASE 1) AND VALVE
CYLINDER (CRANKCASE 1) AND VALVE
M
M
E
B
1
2
3
45 1
2
6
7
Order Job name Q’ty Remarks
Cylinder (crankcase 1) and valveRemove the parts in the order listed 
removalbelow.
Front cover and rear coverRefer to “COVERS” section in CHAPTER 2.
Fuel tankRefer to “CARBURETOR, FUEL TANK
CarburetorAND FUEL PUMP” section in CHAPTER 4.
Cylinder air shroud 1, 2 Refer to “MUFFLER” section.
Engine assembly Refer to “ENGINE REMOVAL” section.
GeneratorRefer to “GENERATOR REMOVAL”
section.
Rocker arm and camshaftRefer to “ROCKER ARM AND
CAMSHAFT” section.
Crankshaft and pistonRefer to “CRANKSHAFT, PISTON
Piston ring AND PISTON RING” section.
1 Spring retainer 2
2 Valve spring 2
3 Valve 1 1
7VV10-03  02.10.4 10:39 AM  Page 29 
						

							ENG
3-30
CYLINDER (CRANKCASE 1) AND VALVE
M
M
E
B
1
2
3
45 1
2
6
7
Order Job name Q’ty Remarks
4 Valve 2 1
5 Stem oil seal 1
6 Oil seal 1
7 Cylinder (crankcase 1) 1
For installation, reverse the removal
procedure.
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							3-31
CYLINDER (CRANKCASE 1) AND VALVE
12 3
a
a
VALVE AND VALVE SPRING REMOVAL
1. Remove:
9Spring retainer 1
9Valve spring 2
9Valve 3
NOTE:
Press the spring retainer by your finger while
removing the spring retainer.
VALVE AND VALVE SPRING INSPECTION
1. Measure:
9Valve stem diameter a
Out of specification →Replace.
2. Measure:
9Valve stem runout
Out of specification →Replace.
NOTE:
The value is half of that indication on the dial
gauge.
3. Measure:
9Valve spring free length a
Out of specification →Replace.
ENG
Valve stem diameter:
3.96 ~ 3.98 mm (Intake)
(0.156 ~ 0.157 in)
3.94 ~ 3.96 mm (Exhaust)
(0.155 ~ 0.156 in)
Limit:
3.92 mm (Intake)
(0.154 in)
3.90 mm (Exhaust)
(0.153 in)
Valve stem runout limit:
0.01 mm (0.0004 in)
Valve spring free length:
25.0 mm (0.984 in)
(Intake/Exhaust)
Limit:
24.0 mm (0.945 in)
7VV10-03  02.10.8 8:09 PM  Page 31