Page 339 of 513
ENGINE
Improper 
air 
fueled 
mixtur
into
cylinder 
walls 
Check 
the 
fuel
system
Seizure 
of
sliding
parts 
Lkl 
rease 
of 
oil
pressure 
Previously 
mentioned
Insufficient
clearances 
Reassemble 
with 
the
designated 
clear
ances
Overheat
Previously 
mentioned
Improper 
fuel 
mixture 
Check 
the
fuel 
system
SERViCE 
JOURNAL 
OR
6UU 
ETIi
l 
REFERENCE
DATE 
JOURNAL 
or
BULLETIN 
No 
PAGE 
No 
SUBJECT
ET 
34
1t 
     
        
        Page 344 of 513
ENGINE
Fig 
EM 
IO 
Intake
manifold
Fig 
EM 
12 
Intake
and 
exhaust
manifolds
Fig 
EM 
It 
Exhaust
manifold
ENGINE 
DISASSEMBLY
CONTENTS
CLEANING 
AND
INSPECTION
DISASSEMBL 
Y 
EM 
4
EM 
5 
PISTON 
AND 
CONNECTING 
ROD
CYLINDER 
HEAD 
EM 
7
EM 
7
CLEANING 
AND 
INSPECTION 
breakage 
rust
damage 
and 
loss
Clean 
the
engine 
thoroughly 
before 
disassembly
Before
cleaning 
the
engine 
remove 
the 
electrical
parts
and
plug 
up 
the 
carburetor 
air 
horn 
to 
avoid 
intrusio 
n 
of
foreign 
matter 
2
Cylinder 
block
Check
thoroughly 
the
water
jacket
for 
cracks 
and
breakage
3 
Clutch
howing 
Check 
for 
cracks
1 
The
engine 
exterior 
Check 
the
covers 
and 
bolts 
for 
4
Oil
pan 
Check 
for 
excessive 
rust
EM 
4 
     
        
        Page 348 of 513

ENGINE
J
I
r 
I
I
J
fj
7
L
j
8
if
d1
I
ilfi
3
c
7
I
t
j
v
1
Ji
Fig 
EM 
27
Valve 
mo 
1
2 
Be 
careful 
not 
to 
lose 
valve
spring 
seat 
oil 
seal 
valve 
collet 
and 
valve 
rocker
spring
O
tj 
AAAftIl
C
e 
WWII
o
glAWle
Fig 
EM 
28
Valve
components
INSPECTION 
AND 
REPAIR
CONTENTS
PREPARATION 
FOR 
INSPECTION 
EM 
8
How 
to 
measure 
cylinder 
bore
EM 
16
CYLlNOER 
HEAD 
AND
80ring 
cylinder 
EM 
16
VALVES
EM 
9
PISTON 
PISTON 
PIN 
AND
Checking 
cylinder 
head
mating 
face 
EM 
9
PISTON 
RING
EM 
18
Valve
assembly 
EM 
9
CONNECTING 
ROD
EM 
19
Valve
spring 
EM 
10 
CRANKSHAFT 
EM
20
Valve 
rocker 
shaft 
and 
rockei 
arms
EM 
lO 
BUSHINGS 
AND 
BEARINGS
EM
21
Valve 
lifter
and
push 
rud
EM 
11
Measuring 
main
bearing 
clearance
EM 
21
Valve
guide 
EM 
11
Measuring 
connecting 
rod
bearing 
clearance
EM 
22
Valve 
seat 
inserts
EM 
12
Fitting 
crankshaft 
bearings 
EM 
22
CAMSHAFT 
AND
CAMSHAFT 
BEARINGS 
EM 
14
Fitting 
camshaft
bushings 
EM 
23
Measuring 
camshaft
bearing 
clearance
EM 
14
MISCELLANEOUS 
COMPONENTS 
EM
24
Valve
timing 
EM 
14 
Crankshaft
sprocket 
and 
camshaft
Checking 
camshaft 
for
bending 
EM 
14
sprocket 
EM
24
CYLlNOER 
BLOCK 
EM 
15
Flywheel 
EM
25
PREPARATION 
FOR 
INSPECTION
L
Check 
the
cylinder 
head 
and
cylinder 
block 
for
traces
of 
water 
leaks 
before
cleaning
2
Clean 
all
parts 
to 
remove 
oil 
stains 
carbon
deposits 
fur 
and 
other
foreign 
matters
completely
3 
Make
sure 
that 
all 
oil 
holes 
are 
clear 
Blow 
air 
into
them 
if
required
4
Secure
proper 
assembly 
carefully
EM
8 
     
        
        Page 350 of 513

ENGINE
2 
The 
valve 
face
or 
valve 
stem 
end 
surface 
should 
be
refaced
by 
using 
a
valve
grinder
Notes 
a 
Deflection 
of 
seat 
surface
against 
axis 
should
be 
0 
03 
mm 
0 
0012 
in 
or 
less
b 
Correctness 
of
right 
angle 
and 
out
of 
round
should 
be 
0 
01 
mm 
0 
0004 
in
or
I
c
EM111
Fig 
EM 
33
Valve
grinder
Note 
When 
the 
a1ve 
head 
has 
been 
reduced 
to 
0 
5 
mm
0 
0197 
in
or
I 
in
thickn 
replace 
the 
al
e
Grinding 
allowance
for 
the 
alve
stem 
end 
surface
is 
0 
5
mm 
10 
0197 
in
or
I
Valve
spring
I 
Measure 
the
free
length 
and 
the 
tension 
of
each
spring 
If 
the 
measured 
value 
exceeds 
the
specified 
limit
replace 
the
spring
Spring
specifications
Free
length 
46 
5 
mm 
1
831 
in
38 
7
rom 
at 
23 
9
kg
1 
524 
in
at 
52 
7Ib
Valve 
closed
Valve
open 
30 
2 
rom 
at 
58 
5
kg
1
19 
in 
at 
1291b
EM 
l0 
2
Check 
each
spring 
for 
deformation 
with 
a
square
Any 
springs 
with
deflection 
of 
1 
6
mm 
0
0630 
in 
or
more 
must 
be
replaced
EM113
Fig 
EM
34 
Valve
spring 
test
Valve 
rocker 
shaft 
and 
rocker 
arm
I
Check 
the 
valve
rocker 
shaft 
and 
rocker 
arm 
for
seizure 
and 
wear 
and
repair 
or
replace 
as
required
Valve 
rocker 
arm 
to 
shaft 
oil 
clearance
0 
02 
to 
0 
05
mm 
0 
0008 
to 
0 
0020 
in
2
When 
valve
contact 
surface 
of 
the 
valve 
rocker 
arm 
is
worn
excessively 
in
step 
repair 
by 
means 
of 
a 
valve
grinder 
or 
replace
Grinding 
allowance 
for 
valve 
contact 
surface 
of 
the
valve 
rocker 
arm 
is 
0 
5 
rom 
0 
0197 
in
or 
less
t
Fig 
EM
3S
val 
Tocker
shaft 
     
        
        Page 354 of 513

ENGINE
CAMSHAFT 
AND 
CAMSHAFT
BEARING
Measuring 
camshaft
bearing 
clearance
Measure
inner 
diameter 
of 
the 
camshaft
bearing 
and
outer 
diameter 
of 
the
camshaft
journaL
If 
camshaft
bearing 
clearance 
is 
excessive
replace 
the
cylinder 
block
assembly
Limit 
0 
15mm 
0 
0059 
in
Standard 
o 
oi 
to 
0 
07mm
M012 
to 
0
0627 
in
Fig 
EM
42
Camshaft 
bearing 
check
1st
2nd
Oil
clearance
mm
in 
3rd
4th
5th
1st
Inner
I 
2nd
I
diameter 
of
I
I
camshaft
3rd
bearing
mm
in
14th 
I
15th 
I 
Standard
0 
037
to 
0 
060
0 
0015
to 
0 
0024
0 
027 
to 
0
050
0 
00
to 
0 
0020
0 
040 
to
0 
063
0 
0016 
to 
0
0025
0 
027 
to
0 
050
0 
0011 
to
0 
0020
0 
037 
to
0 
060
0
0015 
to 
0 
0024
43 
833 
to 
43
843
i
7257 
to 
I 
7261
43
323
to 
43
333
l 
7050 
to 
1
7060
42 
836 
to
42 
846
1
6865 
to 
1 
6868
42
323
to 
42
333
1 
6663 
to
1 
6667
41 
258 
to 
41 
268
1
6243 
to
1 
6247 
Wear 
limit
0 
15
0 
0059
1
1
1
1 
Valve
timing
If
the 
camshaft 
has
no 
apparent 
damage 
although 
some
valve 
troubles 
have 
been 
detected
compare 
valve
timing
data 
with
the 
valve
timing 
diagram 
to 
ensure 
that
beginning 
and
ending 
of 
stroke 
for 
all
cylinden 
are
complying 
with
specified 
advance 
and 
retard
figures
T 
D 
C
DIRECTION 
OF
ROTATION
INTAKE
B 
D 
C
Fig 
EM 
43 
Valve
timing 
diagram
Unit
degree
a 
b 
e 
f
d
c
248 
248 
14 
54 
12
56
Checking 
camshaft 
for
bending
Check 
the 
camshaft 
camshaft
journal 
and 
cam
surface 
for 
bend 
wear 
or
damage
If 
defective 
condition 
exceeds 
the 
limit
replace 
the
defective
part 
s
2
Apply 
a 
dial
gauge 
to 
the 
center
journal 
turn 
the
camshaft 
and 
read 
the 
dial
gauge 
Actual
bend 
is 
a
half 
of
the 
value 
indicated 
on 
the
dial
gauge
Standard 
Bend 
limit
Camshaft 
bend
mm 
in 
0 
015 
0 
0006 
0 
05 
0 
0020
EM 
14 
     
        
        Page 358 of 513

ENGINE
PISTON 
PISTON 
PIN 
AND
PISTON 
RING
Check 
for
seizure 
scratch 
and 
wear
Replace 
as
required
o
10
e
O
I
l
Fig 
EM 
51 
Piston 
and
connecting 
rod
assembly
2 
Measure 
side 
clearance 
of 
each
piston 
ring 
and
ring
groove 
with
the
piston 
ring 
installed
on 
the
piston
Clearance 
of 
a
new
piston 
and
piston 
ring 
should 
be
as
follows
EM129
Fig 
EM 
52 
Side 
clearance 
measurement
EM 
18 
Side 
clearance
Standard 
Wear
limit
mm 
in
mm
in
Top 
ring 
0 
04 
to 
0
Q7
02 
0 
0079
0 
00 
5
to 
0 
0027
2nd
ring 
0 
04 
to 
0
07
0 
0015 
to 
0 
027 
0 
2 
0 
0079
Oil
ring 
0 
04
to 
0 
08
0
0015 
to
0 
0031
I 
0 
2 
0
0079
Ring 
gap
Standard 
Wear 
limit
mm 
in
mm
in
Top 
ring 
0 
2
to 
0
35
1 
0 
0 
0394
0 
0079 
to
0 
0138
2nd
ring 
0 
2
to 
0
35
1 
0 
0 
0394
0 
0079 
to
0 
0138
Oil
ring 
0
3 
to 
0 
9
1 
0 
0 
0394
0 
01 
8
to 
0 
0354
3
Place 
the
ring 
at 
the 
bottom 
of 
the
ring 
traveled
part
of 
cylinder 
bore 
in 
which 
it 
will 
be 
used
Square
ring 
in 
bore
by 
pushing 
it 
into
position 
with 
the
head
piston 
Measure
gap 
between 
ends 
of
ring 
with
feeler
gauge
Gap 
should 
be
as 
listed 
above
Fig 
EM 
53
Ring 
gap 
measurement 
     
        
        Page 361 of 513

ENGINE 
MECHANICAL
Standard 
Maximum
Crankshaft 
bend
mm 
in 
0 
05
0
0020
0
015
0
0006
Note
When 
measuring 
bend 
use 
a 
dial
gauge
Bend 
value 
is
a 
half 
of 
the 
reading 
obtained 
when
the 
crankshaft 
is 
turned 
once 
with 
the 
dial
gauge
applied 
to
its 
center 
journal
3
After 
regrinding 
the 
crankshaft 
fmish 
it 
to 
the
necessary 
size 
indicated 
in 
the 
lists
on
pages 
EM 
25
by
using 
an
adequate 
undersize 
bearing 
according 
to 
the
extent 
of
required 
repair
4 
Install 
the 
crankshaft 
in 
the
cylinder 
block 
and
measure 
the 
thrust 
clearance
Fig 
EM 
60
Crankshaft 
end
pldy 
check
Standard 
Limit
Crankshaft 
free 
end
play 
rom
in 
0 
05 
to 
0
15
0 
0020 
to 
0 
0059 
0
30
0
D118
5 
Check 
the
main 
drive 
shaft
pilot 
bearing 
at 
the 
rear
end 
of 
the 
crankshaft 
for 
wear 
and
damage
Replace 
it 
if
any 
defects 
are 
detected 
BUSHING 
AND 
BEARING
Measuring 
main
bearing
clearance
Check 
all
bearings 
and
bushings 
for 
seizure 
melt 
scar
and
burr
Replace 
bushings 
if
any 
defects 
are 
detected
2
Wipe 
off 
oil
and 
dust
especially 
the 
rear 
of 
the
bushing
3
Set 
the 
main
bearing 
on 
the
cap 
block
Scale
Plastigage
EM141
Fig 
EM 
61
Plastigage
4 
Cut 
a
plastigage 
to 
the
width 
of 
the
bearing 
and
place
it 
in
parallel 
with 
the 
crank
pin 
getting 
clear
of 
the 
oil
hole
Install 
the
cap 
on 
the 
assembly 
and
tighten 
them
together 
with 
the
specified 
torque
Tightening 
torque
5
0 
to 
6
0
kg 
m 
36
to 
43
ft 
lb
Note 
Be
sure 
not 
to 
turn
the 
crankshaft 
when 
the
plastigage 
is
inserted
5 
Remove 
the
cap 
and 
measure 
width 
of 
the
plastigage
at 
its 
widest
part 
with 
the 
scale
printed 
in 
the
plastigage
envelope
EM 
21 
     
        
        Page 362 of 513
ENGINE
Pig 
EM 
62
Bearing 
clearance 
check
Measuring 
connecting 
rod
bearing 
clearance
Measure
connecting 
rod
bearing 
clearance 
in 
the
same
manner
Tightening
torque
3 
2 
to 
3
8
kg 
m 
23
to 
28 
ft 
Ib
Bearing 
oil 
clearance
Standard 
Wear 
limit
Main
bearing
clearance
rom 
in 
0 
020
to 
0 
062
0
0008 
to 
0 
0024 
0 
1
0 
0039
Connecting 
rod
bearing
clearance
mm 
in 
0 
020
to 
0 
050
0 
0008 
to
0 
0020 
0 
1
0 
0039
2 
If 
clearance 
exceeds 
the
specified 
value
replace
bearing 
with 
an
undersize
bearing 
and
grind 
out 
the
crankshaft
journal 
adequately 
Fig 
EM 
63
Bearing 
clearance 
check
Fitting 
crankshaft 
bearings
I 
Set
the 
bushings 
on 
the 
main
bearing 
cap 
and 
the
cylinder 
block
bearing 
recess 
and
tighten 
the
cap 
bolts 
to
the
specified 
torque
Tightening 
torque
5 
0 
to 
5
3
kg 
m 
36 
to 
38 
ft 
lb
2 
Loosen 
the
cap 
bolt 
on
one 
side 
and 
measure
clearance 
between
the
cap 
and
cylinder 
block 
side
n
n
u
ii 
Bearing
6 
Weight
EM143
Fig 
EM 
64
Bearing 
crush 
check
EM 
22