1969 DATSUN 610 fuel cap

t
r

Engine
type

Ovendi
cngth
1300
L
13

Overall
width

Oyerall
height

Turning
circle
din

metres
tfeet
Supen
eded
by

Track
font

rear
1400
c
c

car

Ground
dearance
Olin

Weight
dry
I
820
808

I

Fuel
tClflk
capacity
35
29
6

150
93

Fuel
consumption

aximum
peed
Technical
Data
BLUEBIRD

400
1600
1600

U4
U6

0
4
120
162
20

1
560
6142
410
55
51

420
55
91

10
2
33
5

270
50
0

2
420
95
281

215
8
5

885
1
950
210
8
27

930
2
050

10
1
12

33
2
27
7

50
931
28
2123
5

60
99
L
16

4
215
165
941

1
600
62
99

405
55
3
Ii

0
6
34
8

290
50
79

1
300
51
18

2
500
98
43

185
7
281

955
2
1061

12
14
5

28
2
23
5

60
991
BLUEBIRD
1800
L
18

3
0
5
57

320
5
971

000
2
2051

165
103
BLUEBIRD

1800
ESTATE

U8

4
280
168
501

4
5
557

330
52
361

1
065
2
348

Remove
the
fan

and
pulley
the

right
hand

engine
mounting

and
oil
filter
Remove
the
oil

pressure
switch
Remove
the

following
items
oil
level

gauge
spark
plugs
thermostat

housing

rocker
cover
carburettor
and
inlet
and
exhaust
manifolds

Remove
the
clutch

assembly
as
described
in
the
section

CLUTCH
Remove
the
left
hand

engine
mounting
crankshaft

pulley
water

pump
fuel

pump
fuel

pump
drive
earn
and
cam

shaft

sprocket
See

Fig
A
4
Remove
the

cylinder
head
bolts

in
the

sequence
shown
in

Fig
A

5
and
lift
off
the

cylinder

head
Invert
the
engine
and
remove
the
oil

sump
and
oil

strainer
oil

pump
and
drive

spindle
assembly
front
cover
and

chain
tensioner
Remove
the

timing
chain
oil
thrower
crank

shaft
worm

gear
and
chain
drive

sprocket
See

Fig
A
6
andA
7

Remove
the

connecting
rod

caps
and

push
the

pistons
and

connecting
rods
through
the

top
of
the
bores
as
shown
in

Fig

A
B

Keep
the

connecting
rod

caps
with
their
respective
rods
to

ensure

that

they
are
assembled
in
their

original
positions

Remove
the
flywheel
retaining
bolts
and
withdraw
the

fly

wheel

Fig
A
9
Remove
the
main

bearing
caps
using
the

special
puller
ST
1651
SOOO
to
withdraw
the
centre
and
rear
main

bearing
caps
as
shown
in

Fig
A

l
O
Remove
the
rear
oil
seal

and
lift
out
the
crankshaft
remove
the
baffie

plate
and

cylinder

block
net

Fig
A
II
Remove
the

piston
rings
with
a

suitable

expander
and

press
out
the

gudgeon
pins
under
an
arbor

press

using
the

special
stand
STl300001
as
shown
in

Fig
A

12

Keep

the
dismantled

parts
in
order
so
that

they
can

be
reassembled

in
their

original
positions
Slacken

the
valve
rocker

pivot
lock

nut
and
remove
the
rocker
arms

by
pressing
down
the
valve

springs

Remove
the
camshaft

taking
care
not
to

damage
the

bearings
and
earn
lobes
Withdraw
the
valves

using
the
valve

lifter
STl2070000
as
shown
in

Fig
A
13

ENGINE

Inspection
and
Overhaul

Cylinder
Head
and
Valves

Clean
all

parts
thoroughly
and
remove
carbon

deposits
with

a

blunt

scraper
Remove

any
rust
which
has
accumulated
in

the
water

passages
and
blow

through
the
oil
holes
with

compres

sed
air
to
make
sure

that

they
are

clear

Measure
the

joint
face
of
the

cylinder
head
for
out
of
true

as
shown
in

Fig
A
14

The
surface
should
be
checked
at
various

positions
using
a

straight
edge
and
feeler

gauge
The
permissible

amount
of
distortion
is
0
05
mm
0
0020
in
or
less
If
the

surface
is
out
of
true

by
more
than
the
limit
of
0
1
mm

0
0039

in
it
will
be

necessary
to

regrind
the
head

Clean
each
valve

by
washing
in

petrol
and

carefully
examine

the
stems
and
heads

If
the
stem
is
worn

damaged
or
not

straight
the
valve
must

be
discarded
Check
the

diameter
of
the
stem
with
a
micro

meter

The
diameter
of

the
inlet
valves
should
be
7
965

7
980
mm
0
3136
0
3142
in
and
the
diameter
of

the
exhaust

valves
7
945
7
960
mm
0
3128
0
3134
in

If

the
seating
face
of
the
valve
is

excessively
burned

damaged
or
distorted
it
must
be
discarded
A

badly
pitted

seating
face
should
be
refaced
on
a
valve

grinding
machine

removing
only
the
minimum
amount
of
metal
Renew
the
valve
if
the
thickness
of

the
valve
head
has

been
reduced

by
0
5
mm
0
0197
in
see
Technical
Data
for

valve
dimensions

The

valve
stem

tip

may
be
refaced
if

necessary
the
maxi

mum
allowance
however
is
0
5
mm
0
0197
in

The
valves
can
be

ground
in
to

their
seats
when

completely

satisfactory
The
valve
seats
and
valve

guides
should

be
in

good

condition
and
must
be
checked
as
described
in
the

following

paragraphs

VALVE
GUIDES

Replacement

The
valve
stem
to
valve

guide
clearance
can
be
checked

by

inserting
a
new
valve
into
the

guide
The
stem
to

guide
clearance

should
be
0
020
0
053
mm
0
0008
0
0021
in
for
the
inlet

valves
and
0
040
0
073
mm
0
0016
0
0029
in
for
the
exhaust

valves
If
the
clearance
exceeds
0
1
mm
0
0039
in
for
the

inlet
valves
and
the
exhaust
valves
then
new

guides
should
be

fitted

The
valve

guides
are
held
in

position
with
an
interference

fit
of
0
027
0
049
mm
0
0011
0
0019
in
and
can
be
removed

by
means
of
a

press
and
drift
2
ton

pressure
This
operation

can
be
carried
out
at
room

temperature
but
will
be
more

effectively
performed
at
a

higher
temperature

Valve

guides
are
available
with
oversize
diameters
of
0
2
mm

0
0079
in

if
required
The
standard
valve

guide
requires
a
bore

in
the

cylinder
head
of
11
985
11
996
mm
dia
0
4719

0
4723
in
dia
and
the
oversize
valve

guide
a
bore
of
12
185

12
196
mm
dia
0
4797
0
4802
in

dial

The

cylinder
head

guide
bore
must
be
reamed
out
at

normal
room

temperature

Heat
the

cylinder
head
to
a

temperature
of
150
2000e

302
3920F
before

pressing
in
the
new
valve

guides
Ream

out
the
bore
of
the

guides
to
obtain
the
desired
fInish
and

clearance
Fig
A
IS
The

special
valve

guid
reamer
ST
1103

SOOO
should
be
used
if
available
Valve

guide
inner
diameters

are

specified
in
Technical
Data
at

the
end
of
this
section
The

valve
seat
surface
must

be
concentric
with
the

guide
bore
and

can
be
corrected
with
the

facing
tool
STll670000

Fig
A
16

using
the
new
valve

guide
as
the
axis

VALVE
SEAT
INSERTS

Replacing

The
valve
seat
inserts
should
be
replaced
if

they
show

signs

of

pitting
and
excessive
wear

The
inserts
can
be
removed

by
boring
out
to
a

depth
which

will
cause
them
to

collapse
although
care
must
be
taken
not

to
bore
beyond
the
bottom
face
of
the
recess

in
the

cylinder

head

Select
the
valve
seat

inserts
and
check
the
outer

diameters

Machine
the
recess
in
the

cylinder
head
to

the
following

dimensions
at
room

temperature

9

CENTRIFUGAL
ADVANCE
MECHANISM

Special
equipment
is

required
to
check
the
advance

characteristics
It
is

possible
however
to

carry
out
an
exam

ination
of

the
caffi

assembly
and
the

weights
and

springs
to

ensure
that
the
earn
is
not

seizing

Lift
off
the
distributor

cap
and
turn
the
rotor
anti
clock

wise
When

the
rotor

is
released
is
should
return
to

the
fully

retarded

position
without

sticking
If
it

does
not
return
to
the

fully
retarded

position
it
will
be

necessary
to
check
for

dirt

and
weak

springs

It
should
be
noted
that

any
wear
in
the

mechanism
or

lose
of

spring
tension
will

upset
the
advance
characteristics
and

cause

unsatisfactory
engine
running
performance
over
the

speed

range

VACUUM
ADVANCE
MECHANISM

The

diaphragm
of
the
vacuum
advance

mechanism
is

mechanically
connected
to
the
contact
breaker

plate
The
rise

and
fall
of
inlet
manifold

depression
causes

the

diaphragm
to

move

the
contact
breaker

plate
to

advance
or

retard
the

ignition

If
the
vacuum

control
unit
fails
to

function

correctly
a

check
can
be
carried
out
to
ensure
that
the
contact
breaker

plate

is

moving
freely
and
that
the

three
steel

balls
at

the

top
and

oottom
of
the

plate
are

adequately
lubricated

Also
make
sure
that
the
vacuum
inlet

pipe
is
not
blocked

or

leaking
and
is

securely
tightened

Leakage
may
be
due
to
a

defective

diaphragm
which

should

be
renewed

along
with

any
other

faulty
part
of
the
mechanism

IGNITION
DlSTRffiUTOR
Removal

and

Dismantling

Disconnect
the

battery
leads

2
Disconnect
the

high
tension
lead
at

the
coil

3
Withdraw

the
high
tension
leads
from
the
distributor

cap

4
Detach
the
suction

pipe
from
the
vacuum
control
unit

5
Mark
the

position
of
the
distributor
and
rotor
remove
the

flange
mounting
bolts

and
withdraw
the
distributor

To
dismantle
the
distributor

proceed
as

follows

Take
off
the
distributor

cap
and
remove

the
rotor

Slacken

the
two
set
screws

holding
the
contact
breaker

upper
plate

Remove
the

primary
cable
terminals
and
withdraw
the
contact

set
from

the
distributor
Fig
C
S
Remove
the
vacuum
control

unit

c
Remove
the
two
screws
and
lift
out
the
contact

breaker

plate
detach
the

clamp
the
terminal
and
the
lead

To
remove
the
cam
take
out
the
centre
screw
as

shown
in

Fig
e
6
Drive
out

the
drive

pinion
retaining
pin
with
a
drift

and
hammer
Fig
e
and
remove
the

pinion
and
washer
Take

care
not
to
stretch
or
deform
the

governor
springs
when

detaching

them
from
the

weights

IGNITION
DISTRIBUTOR

Assembling
and

Installing

Assembly
is
a
reversal
of
the

dismantling
procedure

Lubricate
the

moving
contact

pivot
and
smear
the
lobes
of
the

cam
with
multi

purpose
grease

If

the
centrifugal
advance
mechanism
has
been
dismantled

the

governor
springs
and
cams
must
be
refitted
as

shown
in

Fig
e
8
The

governor
weight

pin
6
should
be
fitted
into

the

longer
of
the
two
slots

leaving
a
certain
amount
of

clearance

for
the
start

and
end
of
the

centrifugal
advance
movement

When

installing
the
distributor
take
care
to

align
the

body

and
rotor

with
the
marks
made
during
removal
The
rotor
must

be

positioned
in
its

original
location
it
will
turn

slightly
when

the
distributor
is
inserted
and
the

gear
teeth
mesh
Remove
and

replace
the
distributor
if

the
rotor
does
not

point
to
the

align

ment

mark
until
both
distributor

body
and
rotor
are
correctly

aligned

SPARKING
PLUGS

The

sparking
plugs
should
be

inspected
and
cleaned
at

regular
intervals
not

exceeding

every
10
000
km
6000
miles

New

sparking
plugs
should
be
fitted
at

approximately
20
000

km
12
000
miles

Remove
the

plugs
and
check
the
amount
of
electrode

wear
and

type
of

deposits
Brown
to

greyish
tan

deposits
with

slight
electrode
wear

indicate
that
the

plugs
are

satisfactory
and

working
in

the
correct
heat

range

Dry
fluffy
carbon

deposits
are
caused

by
too

rich
a
mixture

dirty
air
cleaner
excessive
idling
or

faulty
ignition
In
this

case

it
is
advisable
to

replace
the

plugs
with

plugs
having
a

higher
heat

range
Oily
wet
black

deposits
are
an

indication

of

oil
in

the
combustion
chambers

through
worn

pistons
and

rings
or
excessive
clearance
between
valve

guides
and
stems

The

engine
should
be
overhauled
and
hotter

plugs
installed
A

white
or

light
grey
centre

electrode
and
bluish
burned
side

electrode
indicates

engine
overheating
incorrect

ignition
timing

loose

plugs
low
fuel

pump
pressure
or
incorrect

grade
of
fuel

Colder

sparking
plugs
should
be
fitted

The

plugs
should
be
cleaned
on
a

blasting
machine
and

tested
Dress
the
electrodes
with
a
small
file
so
that
the
surfaces

of
both
electrodes
are
flat
and

parallel
Adjust
the
spark
plug

gap
to
0
8
0
9
mm
0
031
0
035
in

by
bending
the
earth

electrode
Refit
the

plugs
and

tighten
them
to
a

torque
reading

of
1
5
2
5

kgm
II
15Ib
ft

31

Fuel

System

DESCRIPTION

FUEL
TANK

FUEL
PUMP

CARBURETTOR
IDLING
ADJUSTMENT

FAST
IDLE
OPENING
ADJUSTMENT

THROTTLE
VALVES
INTERLOCK
OPENING

DASHPOT

DESCRIPTION

The

diaphragm
type
fuel

pump
shown
in

Fig
D
1
feeds

fuel

from
the
tank
to
the
carburettor
in
a

regulated
supply

according
to
the
needs
of
the

engine
A
cartridge
type
fuel

strainer

prevents
any
dirt
from

reaching
the

pump
inlet
valve

The

carburettor
fitted
to

the

engine
is
either
a
down

draught
two
barrel

type
equipped
with
a
throttle

operated

acceleration

pump
and
power
valve
mechanism

See
Fig
D
2

or
a
twin
SU
carburettor
of
the

type
shown
in

Fig
D
3
In
the

two
barrel

type
carburettor

fuel
flows
from
the

passage
at
the

bottom
of
the
float
chamber

passes
through
the

primary
main

jet
and
mixes
with
air

introduced

through
the
main
air
bleed

screw

The

petrol
and
air
mixture
is

injected
into
the
venturi

through
the
main
nozzle

Each
time
the
accelerator

pedal
is

depressed
the
throttle

opens
and
the
accelerator

pump
forces
a

jet
of

petrol
into
the

air
stream
to
allow
the

engine
to
accelerate

smoothly
See

Fig

0
4
The

power
valve
mechanism
is

operated
automatically

according
to
the
demands
made

by
the

engine
Under
light
load

i
e

part
throttle
conditions
the
intake
manifold

depression
is

transmitted
below
the
throttle
valve
the
vacuum

pulls
a

piston

upwards
against
a

spring
and
leaves
the

power
valve
closed

allowing
additional
air
to
be

admitted
through
the
air
bleed
screw

and
thereby
weaken
the

petrol
and
air
mixture
When
the
vacuum

below
the
throttle
vaJve
is
lowered

during
full
load
conditions

the

piston
is

pushed
down
opening
the

power
valve
and
providing

additional
fuel
to
enrichen
the
mixture

The
model

HJ
L
38W6
SU
twin
carburettor
is
of

the

horizontal
variable
venturi

type
and
is
used

only
on
the
1600

and
1800
cc

engines
In
this

type
of
carburettor
a

constant

flow
of
intake
air
is

maintained

by
the

automatically
adjusted

venturi

opening
this
is
accomplished

by
the
suction

piston

sliding
in
accordance
with

changes
in
the
volume
of
intake
air

Referring
to

Fig
D
5
the
suction
chamber
is
mounted
above

the
venturi
The
suction

piston
slides
vertically
within
the

chamber

and

changes
the
venturi

opening
area
The

piston
is

operated
by
a

difference
between
the

upper
vacuum

pressure

which
is

applied
through
the
suction

poct
and
the
atmospheric

pressure
which

is
introduced

through
the
air
hole
from
the
air

cleaner

The
amount

by
which
the
throttle
is

opened
causes
the

suction

piston
to
rise
or
fall
under
the
intluence
of
the

engine

suction
The

pozzle

opening
therefore

changes
and

provides
an

optimum
air
fuel
mixture
at
all

engine
speeds

The

cartridge
type
fuel
strainer
utilizes
a
fibre
strainer

element
which
should
be

replaced
every
20
000
km
12
000

miles
Removal
of
the
fuel
strainer
is
a

simple
operation
but
as

it
cannot
be
drained
the
strainer
should
not
be
removed
when
CARBURETIOR
Removal
and
Overhaul

FLOAT
LEVEL
Adjustment

SU
TWIN
CARBURmORS

Adjustments

SU
TWIN
CARBURmORS

Dismantling

SU
TWIN
CARBURETTORS

Inspection

STARTING
INTERLOCK
VALVE
OPENING

HYDRAULIC
DAMPER

the
tank
is

full
unless

absolutely
necessary

A

viscous

paper
type
air
cleaner
element
is
fitted
which

does
not

require
cleaning
and
should
be

repl
ced

every
40
000
km

24
000
miles
The
air

cleaner
fitted
on
the

single
carburettor

is
equipped
with
an

idling
compensator
to

prevent
the
mixture

from

becoming
too

rich
at

high
idling

temperatures
Additional

fresh
air
is
introduced
into
the
inlet
manifold

by
the
action
of

a
bimettalic

strip
located
in
the
air
cleaner
When
the

temperature

under
the
bonnet
is

high
the
bimetal
is

heated

by
the
hot
inlet

air
and
lifts
to
allow
the
valve
to

open
The

idling
compensator

valve

partially
opens
at

550
I310F
and
is

fully
open
at

650C

l490F
The
unit
cannot
be
dismantled
as

it
is

pre
sealed
and

correctly
adjusted
for
valve

timing
Fig
D
6
shows
the

layout

of

the
idling
compensator
piping

FUEL
TANK

Replacing

The
fuel
tank
can
be
removed
in
the
following
manner

Remove
the
rear
seat

and
back
rest

2
Take
out
the
board
behind
the
back
rest

3
Take
out
the

luggage
compartment
lining
board
and

disconnect
the
cable
to
the

petrol
gauge
unit

4
Disconnect
the
petrol
filler
tube
from
the
tank

5
Remove
the
tank
retaining
bolts
and
disconnect
the

rubber
fuel
outlet
and
return
hoses

Installation
is

a
reversal
of
the
removal

procedure
always

ensure
that
the
fuel
lines
arc
carefully
checked
for

signs
of

damage
before

replacing
the
tank

FUEL
PUMP

Testing

Pressure
and
capacity
tests
can
be
carried
out
with
the

pump
installed
in
the

following
manner

Static

pressure
test

Disconnect
the
fuel
line
at

the
carburettor
install
an

adaptor
tee

fitting
and
suitable

pressure
gauge
to
the
fuel
line

between
carburettor
and
fuel

pump
Start
the
engine
and
run
it

at

varying
speeds

The

reading
on

the
gauge
should
be
0
18
0
24

kg
sq

cm
2
6
34
Ib

sq
in
If
the

pressure
is
below
the

specified

figure
then
either
one

part
of
the

pump
has
worn

excessively

or

general
wear
has
occured
to

all
the

working
parts
The
faults

may
include
a

ruptured
diaphragm
worn
and

warped
valves

33

and
seats
or
a
weak

diaphragm
return

spring

A

pressure
above
the

specified
figure
may
be
due
to

an

excessively
strong
and
tight
diaphragm

Capacity
test

The

capacity
test
can
be

carried
out
when
the
static

pressure
has
been
tested
and
conforms
with
the

specified
figure

of
0
18

kg
sq
cm
2
6Ib

sq
inJ

Disconnect
the
fuel
line
at

the
carburettor

and

place
a

container
under
the
end
of
the

pipe
to
act
as
a
fuel

sump

Start
the

engine
and
run
it
at
a

speed
of
1000

Lp
m
The

amount

of
fuel
delivered
from
the

pump
in
one
minutc
should

be

1000
cc
2
1
US

pt

If

petrol
does
not
flow
from
the

opcned
end
of

the
pipe

at
the
correct
rate
then
either
the
fuel

pipe
is

clogged
or

the

pump
is
not

operating
correctly

If
the
latter
cause
is

suspected
the

pump
must
be
removed

and

inspected
as
described
below

FUEL
PUMP

Removing
and

Dismantling

Before

removing
the
pump
take
off
the

petrol
tank

cap

and
disconnect
the

pump
inlet
and
outlet

pipes
Blow

through

the

pipes
with

compressed
air
to

make
sure

that

they
are
not

clogged

Remove
the

pump
retaining
nuts

withdraw
the

pump
and

dismantle
it
in
the

following
order

Referring
to

Fig
D
l

Take
out
the
screws

holding
the
two

body
halves

together

and

scparate
the

upper
body
from

the
lower

body

2
Remove
the

cap
and

cap
gasket

3
Unscrew
the
eI
bow
and
connector

4
Take
off

the
valve
retainer
and
remove
the
two
valves

5
To
remove
the

diaphragm
diaphragm
spring
and
lower

body
sealing
washer

press
the

diaphragm
down

against

the
force
of
the

spring
and
tilt
the

diaphragm
at
the
same

time
so
that
the

pull
rod
can
be
unhooked
from
the
rocker

arm

link

Fig
D
7

The
rocker
arm

pin
can

be
driven
out
with
a
suitable

drift

FUEL
PUMP

Inspection
and

Assembly

Check
the

uppcr
and

lower

body
halves
for
cracks

Inspect

the
valve
and
valve

spring
assembly
for

signs
of
wear
and
make

sure
that
the

diaphragm
is
not

holed
or

cracked
also
make
sure

that
the
rocker
arm
is
not
worn
at
the

point
of
contact
with

the

camshaft

The
rocker
arm

pin
may
cause

oil

leakage
if
worn

and

should
be
renewed
Assembly
is
a
reversal
of
the
dismantling
procedure

noting
the

following
points

Fit
new

gaskets
and
lubricate
the
rocker
arm
link
and
the

rocker
arm

pin
before

installing

The

pump
can
be
tested

by
holding
it
approximately
I

metre
3

feet
above

the
level
of
fuel

and
with
a

pipe
connected

between
the
pump
and
fuel
strainer

Operate
the
rocker
ann

by
hand
the

pump
is

operating

correctly
if
fuel
is
drawn

up
soon
after

the
rocker
ann
is

released

CARBURETTOR
IDLING
ADJUSTMENT

The

idling
speed
cannot
be

adjusted
satisfactorily
if
the

ignition
timing
is
incorrect

if
the
spark
plugs
are

dirty
or
if

the
valve
clearances
are
not

correctly
adjusted

Before

adjusting
the

idling
speed
set
the
hot
valve

clearances

t
o
0
25
mm
0
0098
in
for
the
intake
valves

and

0
30
mm
0
0118
in
for
the
exhaust
valves
as
described
in

the
ENGINE

section

Idling
adjustment
is
carried
out

with
the
throttle

stop

screw
in

conjunction
with
the

idling
adjustment
screw

See

Fig
D
8

Run
the

engine
until
it
attains
its
normal

operating

temperature
and
then
switch
off

Starting
from
the
fully
closed

position
unscrew
the

idling
adjustment
screw

by
approximately
three
turns

Screw
the
throttle

stop
screw
in

by
two
or
tftr
e
turns
and

start

th
engine

Unscrew
the
throttle

stop
screw
until
the

engine
commences

to
run

unevenly
then
screw
in
the

idling
adjustment
screw
so

that
the
engine
runs

smoothly
at
the

highest
speed

Readjust
the
throttle

stop
screw
to

drop
the

engine
speed

of

approximately
600
r

p
m
is
obtained

WARNING
Do
not

attempt
to
screw

the

idling
adjustment

screw

down
completely
or
the

tip
of
the
screw

may
be

damaged

FAST
IDLE
OPENING
ADJUSTMENT

The
choke
valve
is

synchronized
with
the
throttle
valve

and
connected
to
it

by
levers
as
shown
in

Fig
D
9
The
fast

idle
opening
can
be
check

by
fully
closing
the
choke
valve
and

measuring
the
clearance
between
the

primary
throttle
valve
and

the
wall
of

the
throttle
chamber
This
clearance

being
shown

as
A

in
the
illustration
The
clearance
for

the
carburettor

types
is
as
follows

Carburettor

type
Throttle

opening

angle

180

180

190
Dimension
A

213304
361

13304
4
I

13282
331
1
55mm
0
06lin

1
55mm
0
06Iin

1
3
mm
0
051
in

35

inter
ill
j

@
pl

T
i

5

12

Fig
D
3

View
of
the
SU
twin

type
carburettors

1

Throttle
r

2
JaJana

crew

Front
throttle

adjusting
screw

4

AuxiliDry
shoft

5
Ftnt
idle

selling
lCn
W

6

Throttle

shaft

7
Rear
throttle

adjusrint
screw

8

Idling
adjustment
nuts

m

11

j
G

36
B

l
D

i
I

lli

9
3
J6

6

Fig
D
4

Accelerator

pump
mechanism

J

Pump
injuror

2

Weight

2
Outklvolve

4
Piston

5

Damper
spring

6
Piston

return

spring

7

Clip

8
Strainu

9
Inlet
lmlJe

I

Fig
D
6

Idling
compensator
1

lit

21
Fig
D
5
Section

through
the
SU
twin
carbureUor

J
Suction

chamber

Suctiull

spring

3
Hoat

chamber
corer

4
Guide

5

Nipple

6
Throttle
chamber

7
Piston
rod

8

Needle
valve

9
T7trollle
l
ob
e

J
O
Float
chtzmber

J
1
Float
Iel
cr
J
2
Float

13
Sleel
e

4

aip

5
Fuel
hose

6
Oil

cap
nut

1
7

Plunger
rod

18
Transvtne
hole

J
9
Oil

domJX

20
Suction

piston

21
Nozzle

Idling
adjustment
nut

Connect
the
fuel
line
from
the
float

chamber
to
the
nozzle

nipple
and

tighten
the

retaining
clip
Pull
out

the
choke
lever

and

place
the

connecting
plaie
betw
n
the
washer
and
sleeve

collar
Screw
the

plate
to
the

nozzle
head
and
check
that
the

collar
is
installed
in
the
hole
in

the

plate
by
mo

ing
the
choke

lever
as

necessary

Recheck
the

piston
to
make

sure
that
it
falls

freely
without

binding

SU
TWIN
CARBURETTOR

Centering
the

jet

Remove
the

damper
oil

cap
nut

and
gradually
raise
the

lifter

pin
4
in

Fig
D
17

Continue
to
raise
the
lifter

pin
until
the
head
of
the

pin

raises
the

piston
by
approximately
8
mm
0
31
in
When
the

lifter

pin
is
released
the

piston
should

drop
freely
and
strike

the
venturi
with
a

light
metallic
click
If

the

pi
ston
does
not

fall

freely
it
will
be

necessary
to
dismantle
the

carburettor
in

the
manner

previously
described

SU

TWIN
CARBURETTOR

FLOAT
LEVEL

Inspection
and

Adjustment

The
fuel
level
in
the
float
chamber
can

be
checked

using

the

special

gauge
ST
19200000
Remove
the
float
chamber

drain

plug
and
install
the

special

gauge
as
shown
in

Fig
D
20

Start
the

engine
and
allow
it
to
run
at

idling
speed
The

fuel
level
is
conect
if
it
is

indicated
on

the

glass
tu

be
at
a

distance
of
22
24
mm
0
866
0
945
in
below
the

top
of
the

float
chamber

The
level
of
the
fuel
can

be
corrected
if

necessary
by

adjusting
the
float
level
in
the

following
manner
Take
out
the
float
chamber
coveT

securing
screws
and

lift
off
the
cover
and
attached
float

lever
Hold
the
cover
so
that

the
float
lev
r
is

facing
upwards
Lift
the
float
lever
and
then

lower
it
until
the
float
lever
seat

just
contacts

the
valve
stem

The
dimension
uH
in

Fig
D
1
should
be
11
12
mm
0
43

0
47
in

and
can

be
corrected

by
bending
the
float
lever
at
the

point
indicated

SU
TWIN
CARBURETTOR

Starting
interlock
valve

opening
adjustment

To

adjust
the
starting
interlock

opening
the

connecting

rod
4
in

Fig
D
22
1
must
be
bent

using
a
suitable

pair
of

pliers
The
throttle

opening
can

be
increased

by
lengthening

the

connecting
rod
or
reduced

by
shortening
the
rod

The
throttle

opening
is
correctly

adjusted
when
the

clearance
8

between
the
throttle
valve
and
throttle
chamber

is
set
to
0
6
mm
0
023
in
with
the
choke
lever
half

completely

out

HYDRAULIC
DAMPER

The

damper
oil

should
be
checked

approximately
every

5000
km
3000
miles
To
check
the
oil
level
remove
the
oil

cap
nut
as
shown

in

Fig
D
23
and
check
the
level
of
oil

against

the
two

grooves
on
the

plunger
rod

Top

up
with
SAE
20

engine
oil
if

the
oil
level
is
below
the
lower
of
the
two

grooves

Take
care

not
to
bend
the

plunger
rod
when

removing
and

replacing
the
oil

cap
nut

and
make
sure
that
the
nut
is

sufficiently

tightened
by
hand

TechnIcal
Data

Engine
Model
Ll4

I400cc

Primary
Secondary

28mm
32mm

21x7mrn
28xlOmm

96

165

60
60

I
Omm

220
100

1
6
Outlet
diameter

Venturi
diameter

Main

jet

Main
air
bleed

1
st

slow
air
bleed

2nd
slow
air
bleed

Economizer

Power

jet

Float

level

Fuel

pressure

Main
nozzle
55

22mm

0
24

kg

sq
cm
3
41b

sq
in

2
2mm

2
Smm

SU
Twin
Carburettors

Type

Bore
diameter

Piston
lift

Jet
needle

Nozzle

jet
diameter

Suction

spring
IUL
38
W6

38mm

1
4961
in

29mm

1417
in

M
76

2
34
mm

0
0921
in

No
23

Float
needle
valve

inner
diameter

Float

level
1
5mm
0

059
in

23mm
0
9055
in

42
Ll6
1600cc

Primary

Secondary

28mm
32mm

22x7mm

29xlOmm

102
165

60

60

1
0mm

180
100

1
6
Ll8

l80Occ

Primary
Secondary

30mm

34mm

23x14x7mm
30xlOmm

102
170

60
60

I
Omm

210
100

1
6

55

22mm
55

22m

2
3mm
2
5mm
2
3mm
2
8mm

Throttle

clearance
at
full

throttle

Position
at
full
throttle
0
6mm
0
0236
in

6
50

FUEL
PUMP

Type

Delivery
amount
Mechanical

1000cc
minute
at
1000

r

p
m

0
18
0
24

kg

sq
cm

2
5
3
41b

sq
in

from
eccentric
on
cam

shaft
Delivery

pressure

Drive

Trouble
Shooting

Ignition
System

SYMnONS
be
d
t
f
I
h

ENGINE
CRANKS
IUT
DOES
NOT
nART

ENGINE
STARTS
BUT
RUNS
FOR
SHORT

PERIODS
ONLY

ENGINE
MISfiRES
AT
LOW
SPEED

ENCINE
WlSflRES
AT
HIGH
SPEED

ENGINE
MISFIRES
AT
ALL
SPEEDS

ENCINE
MISfiRES
ON
ACCELERATION

AND
FAI
TO
REV

ROUGH
IDLE

ENGINE
RUNS
ROUCH
AT
toGH
SPEED

UCK
OF
POWER

POOR
ACCELERAnON

LACK
OF
TOP
SPEED

EXCESSIVE
FUEL
CONSUMmON

PlNKlNC
PROBABLE
CAU5E

t
Bani
dilcharFd
01
defective

b
COJlIllCl
nabr
poinb
nCiCCl
c1Unlftl
renewlna

c
Incorrect
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ktr
potftu

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ConllCt
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Spark
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ch
ntnl
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r
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llpulpl1llPpI

WronllypeoCap
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h
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lllon
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I
Coli
c
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defC
tl

t
g
o
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c
o
c
t1o
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n
h
CllIl
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toil

H
T
lud

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Open
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lIlort
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conneclion
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spart

m
l
1ulludslnCClfRcllyc
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tcd

H
T
Ink
coil
dbtribulor
elp
due
oil
din

mol
t
I
o
d
ml

C
ntrlfuplld
anee
not
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lctly

p
VKuum
Id
e
not
funclionill
cOIYKtly

q
om
datrlbutw
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ld

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b
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j

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b
Clean
01
n

c
Fi
wrrecl
poin

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Renew
blnker
ll
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l
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Fit
cor
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k
True
ndlecfity

Tnee
nd
leclity

m
Con
c
cOI
ct1r

Clca
wIth
dry
hn
fne
rl

EllImlne
and
Oillpllln
ly

p
Cheek
Ind
rectlly

q
aepllccddectkol
plnl

r
Chlnp
comct
Il
adl
of
fuel
Fuel
System

ENGINE
CRANKS
8lTf
DOES
NOT
START

ENGINE
STARTS
BUT
RUNS
FOR
SHORT

PERIODS
ONLY

ENGINE
MISARES
AT
LOW
SPEED

ENGINE
MISflRE5
AT
HIGH
SPEED

ENGINE
MISFIRES
AT
ALL
SPEEDS

ENGINE
MISAKES
ON
ACCELERA110N

AND
FAILS
TO
REV

ROUGH
IDLE

ENGINE
RUNS
ROUGH
AT
HIGH
SPEED

LACK
OF
POWER

POOR
ACCELERA110N

LACK
OF
TOP
SPEED

EXCESSIVE
flJEL
CONSUMmON

PINKING
BACKFIRE
PROBABLE
CAU5E

Fuel
tank
empty

b
Fu
llinc
blocked

Fuel
pumpd
fectiYe

d
Block
in
cllburene

Air
lock
in
fuel
line

f
Fuel
rut
r
blocked

I
Cuburetter
needle
nlve
jammed

h
Wile
CI
buRlt
r

Errltic
fllel
now
due
blocka

j
IdlinJlpeed
too
low

k
InConectlCtllnlofcttoke
conllol

1
lncorrectcarbuntterfuel
nOltlewl

m
C
muretler
Itlna

Ail
leak
It
Inlet
mlrurold

Incorrect
pade
offuet

p
Carburetter
accelerator
pumpdefect
e

q
Throlll
lintl
rrlIIl
djUlled

IncofftCl
Idjullmenl
of
IdlmJ
mutU
e

Aif
nltef
elogcd

Incorm
t
lpiitiOlluminJ

Clrburellel
Pll
un
lIitkln

Wron
cllburenerjetl
Atled
YMPtO

I
bell
f
1
h
I
j
k
I
m
nOli
I
I
I
0

b
f
h
i
J
k
I
m
REMEDIES
q

FLllllnk

b
Blow
ObSIf1rCllUll
ilh
compl
t
lIed

R
pll
pump

d
RemO
l
e
blockaJe

Trace
Uld
bleed
QUI

r
CIUl1fi1tef

K
Fretne
dle

h
Drlln
d
yout

Removeblockq

J
Adju
throlllelfOl

k
Reset
conllol

1
AdjUSlle
e

m
Wlit
fOI
melt
If
pt
nLS
n
nu

Tlact
lelklndse
a1

Dllu
e
fuel
with
hlah
I
rllln
ubl
ln
blc

p
Trace
fault
and
reeufy

q
AdjuII
correelly

Adju
mutufWconlrol

Clnnnlttr
Retjme
Ilftn

OdClrbulelle
Repllce
Wllh
Je