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.
7VV10-03  02.10.4 10:39 AM  Page 22 

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...

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...

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...

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...

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...

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)
7VV10-03  02.10.4 10:39 AM  Page 28 

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”...

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.
7VV10-03  02.10.4 10:39 AM  Page 30 

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...