Suzuki 1980 GSX400 User manual

FOREWORD
The
SUZUKI
GSX400
has
been
developed
as
a
new
generation
motorcycle
to
the
GS
models.
It is
packed
with
highly
advanced
design
concepts
including
a
forged one
piece
crankshaft
assembly
and
a
new highly
efficient
combustion
system
(TSCC).
Combined
with
precise
control
and easy
handling,
the
GSX400
provides
excellent performance and
outstanding
riding
comfort.
This
service
manual
has
been
produced
primarily
for
experienced
mechanics
whose
job
is
to
inspect, adjust,
repair
and
service
SUZUKI
motorcycles.
Apprentice
mechanics
and
do-it-yourself
mechanics,
will
also find
this
manual
an
extremely
useful
guide.
Model
GSX400
manufactured
to standard
specifications is
the
main
subject
matter
of
this
manual.
However,
the GSX400 machines
distributed
in
your
country
might differ
in
minor
respects
from the
standard-specification
GSX400
and,
if
they
do,
it is because
some
minor
modifications
(which
are of
no consequence
in most
cases as
far
as
servicing
is
concerned)
had
to
be made
to comply
with
the
statutory
requirements
of
your country.
This
manual
contains
up-to-date
in formation
at
the
time
of its issue.
Latermade
modifi
cations
and
changes
will
be explained
to
each
SUZUKI
distributor
in
respective
markets,
to
whom
you
are
kindly
requested
to
make
query
about
updated
information,
if
any.
NOTE:
This
service
manual
gives
only
servicing
procedures
which
differ
from those
of
the
GSX25O
and describes
the
new
features
of
the
GSX4OU
Before
performing
any
servicing,
please
read
thoroughly
GSX25O
service
manual
SUZUKI
MOTOR
CO.,LTD.
Administration Department
Overseas
Service
Division
Quoting,
copying
or
otherwise using any
part
of
this manual
without
ex
plicit
authorization
from
Suzuki
Motor
Co.,
Ltd.
is
not
permitted
as all
rights
to
the publication are
reserved
under
copyright law.

CONTENTS
VIEW
OF
SUZUKI
GSX400E
1
BREAKING-IN
RIMIN
2
SPECIFICATIONS
2
ENG1NE
CYLINDER HEAD COVER 4
VALVE
AND
CAMSHAFT
5
CYLINDER HEAD 7
CYLINDER,
PISTON
AND RING 8
CRANKSHAFT
AND
CONNECTING
ROD 9
COUNTER
BALANCER
11
CRANKCASE
13
TRANSMISSION..
15
GEARSHIFT
CAM
AND FORK 18
CLUTCH
AND
OIL
PUMP 19
STARTER
CLUTCH
AND GENERA
TOR 22
EXHAUST
PIPE
AND MUFFLER 23
CARBURETOR 24
LUBRICATION
SYSTEM
25
SPEEDOMETER
AND
TACHOMETER 26
STEERING
STEM
27
REAR
WHEEL 32
WIRING
DIAGRAM
33
WIRE ROUTING 37
CABLE
ROUTING
39
SPECIAL
TOOLS
40
TIGHTENING
TORQUE
41
SERVICE
DATA
44

BREAKING-IN
R/MIN
Keep
to
these
breaking-in engine
speed limits:
SPECI
Fl
CATI
ONS
DIMENSIONS
AND
DRY
MASS
Overall
length
2 075
mm
Overall
width
755
mm
Overall
height
1 075
mm
Wheelbase
1 385
mm
Ground
clearance
155
mm
Seat
height 815
mm
Dry
mass
175
kg
ENGINE
Type
Four-stroke,
air-cooled, DOHC
Number
of
cylinders
2
Bore
67.0
mm
Stroke
56.6
mm
Piston
displacement 399
cm 3
Compression
ratio
10.0
:
1
Carburetor
MIKUNI
BS34SS,
twin
Air
cleaner
Polyurethane foam
element
Starter
system Electric
Lubrication
system
Wet
sump
TRANSMI
SSI
ON
Clutch
Wet
multi-plate
type
Transmission
6-speed
constant
mesh
Gearshift
pattern
1-down,
5-up
Primary
reduction 2.714
(76/28)
**Final
reudction
2.750
(44/16)
Gear
ratios,
Low
2.46
1
(32/13)
2nd
1.777
(32/18)
3rd
1.380
(29/21)
4th
1.125
(27/24)
5th
0.961
(25/26)
Top
0.851
(23/27)
Drive
chain
DAIDO
DID5OUB,
104
links
**Modification
of
Rear
sprocket for
manufactured
on
and
after
June,
1981
[2.812
(45/16)1
1
GSX400E GENERAL INFORMATION
VIEW
OF
SUZUI(I
GSX400E
1
b
-
At
GSX400E GENERAL INFORMATION
2
Initial 800
km Below
4,000
r/min
Up
to
1,600
km Below
6,000
r/min
Over
1,600
km
Below
9,500
r/min
I
i
I
RIGHT
SIDE
LEFT
SIDE

BREAKING-IN
R/MIN
Keep
to
these
breaking-in engine
speed limits:
SPECI
Fl
CATI
ONS
DIMENSIONS
AND
DRY
MASS
Overall
length
2 075
mm
Overall
width
755
mm
Overall
height
1 075
mm
Wheelbase
1 385
mm
Ground
clearance
155
mm
Seat
height 815
mm
Dry
mass
175
kg
ENGINE
Type
Four-stroke,
air-cooled, DOHC
Number
of
cylinders
2
Bore
67.0
mm
Stroke
56.6
mm
Piston
displacement 399
cm 3
Compression
ratio
10.0
:
1
Carburetor
MIKUNI
BS34SS,
twin
Air
cleaner
Polyurethane foam
element
Starter
system Electric
Lubrication
system
Wet
sump
TRANSMI
SSI
ON
Clutch
Wet
multi-plate
type
Transmission
6-speed
constant
mesh
Gearshift
pattern
1-down,
5-up
Primary
reduction 2.714
(76/28)
**Final
reudction
2.750
(44/16)
Gear
ratios,
Low
2.46
1
(32/13)
2nd
1.777
(32/18)
3rd
1.380
(29/21)
4th
1.125
(27/24)
5th
0.961
(25/26)
Top
0.851
(23/27)
Drive
chain
DAIDO
DID5OUB,
104
links
**Modification
of
Rear
sprocket for
manufactured
on
and
after
June,
1981
[2.812
(45/16)1
1
GSX400E GENERAL INFORMATION
VIEW
OF
SUZUI(I
GSX400E
1
b
-
At
GSX400E GENERAL INFORMATION
2
Initial 800
km Below
4,000
r/min
Up
to
1,600
km Below
6,000
r/min
Over
1,600
km
Below
9,500
r/min
I
i
I
RIGHT
SIDE
LEFT
SIDE

3
GSX400E GENERAL INFORMATION
ENGINE
GSX400E
4
ENGINE
CHASSIS
Front
suspension
Rear
suspension
Steering
angle
Caster
Trail
Turning
radius
Front
brake
Rear
brake
Front
tire
size.
Rear
tire size
Front
fork
stroke
Rear wheel
travel
Front
tire
pressure
Rear
tire pressure
Spark plug
.
Battery
Generator
.
Fuse
CAPACITI
ES
Fuel
tank
including
reserve.
Reserve
Engine
oil
Front
fork oil
(each
leg)
Telescopic,
oil dampened
• Swing
arm,
oil
dampened
spring
5-way
adjustable
42° (right
&
left)
62° 00’
.2.4m
Disc
brake
Internal
expanding
3.OOS1B
4PR
3.50S18
4PR
3.75S18
4PR
(for
W. Germany
and
Denmark)
.140mm
.100mm
175
kPa
(Normal
200
kPa
(Normal
(1.75
kg/cm 2
solo
riding)
(2.00
kg/cm 2
solo
riding)
Battery
ignition
(for General)
Fully
transistorized
(for
the
others)
Contact
point
type
20°
B.T.D.C.
below
at
1 650
r/min
and
35°
B.T.D.C.
above
at 3 500 r/min
Fully
transistorized
type
20°
B.T.D.C.
below
at 1
650
r/min
and
40°
B.T.D.C.
above
at
3 500
r/min
NGK
DBEA/DR8ES-Lor
NIPPON
DENSO
X24ES-U/X24ESR-U
12V
43.2
kC
(12
Ah)/10
HR
Three-phase A.C.
generator
14.5
L
(3.2
Imp
gal)
3.0
L
(2.6
Imp
qt)
2.6 L
(2.3
Imp
qt)
..145
ml
(5.11
lmpoz)
CYLINDER
HEAD
COVER
REMOVAL
•
It
is unnecessary
to
remove
four
cover
cap
bolts
®
before
removing
cylinder
head cover
®.
Four
bolts
®
cannot
be
remove
unless
camshaft
end
caps
®
are
not
removed.
I
NSTALLATI
ON
•
Be
sure to
replace
gaskets
®
and
®
with
new
ones.
•
Fill approx.
50
ml of
engine
oil in
four
pockets
of
the
cylinder
head
before
mounting
the
head cover
on
the
cylinder
head.
•
Set two
positioning
pins
at
proper
position
and
tighten
with
long
bolts
(6
x
35mm).
• Apply
small
amount
of
SUZUKI
thread
lock
cement
on
screw
®
which
clamps
camshaft
end cap
®.
• Install
tachometer
drive gear
after
cylinder
head
cover
is
fitted
to
the
cylinder
head.
• Gasket
®
should
be
fit
that
breather
hole
side
faces
toward
front.
105mm
ELECTRI
CAL
Ignition
type
Ignition
timing
15A
*
These
specifications
are subject
to
change
without
notice.
99000-32040
I
Suzuki
Thread
lock
]
cement
TIGHTENING TORQUE
Bolt(j,®and®
9—
10
N.m
(0.9—1.0kg-rn)

3
GSX400E GENERAL INFORMATION
ENGINE
GSX400E
4
ENGINE
CHASSIS
Front
suspension
Rear
suspension
Steering
angle
Caster
Trail
Turning
radius
Front
brake
Rear
brake
Front
tire
size.
Rear
tire size
Front
fork
stroke
Rear wheel
travel
Front
tire
pressure
Rear
tire pressure
Spark plug
.
Battery
Generator
.
Fuse
CAPACITI
ES
Fuel
tank
including
reserve.
Reserve
Engine
oil
Front
fork oil
(each
leg)
Telescopic,
oil dampened
• Swing
arm,
oil
dampened
spring
5-way
adjustable
42° (right
&
left)
62° 00’
.2.4m
Disc
brake
Internal
expanding
3.OOS1B
4PR
3.50S18
4PR
3.75S18
4PR
(for
W. Germany
and
Denmark)
.140mm
.100mm
175
kPa
(Normal
200
kPa
(Normal
(1.75
kg/cm 2
solo
riding)
(2.00
kg/cm 2
solo
riding)
Battery
ignition
(for General)
Fully
transistorized
(for
the
others)
Contact
point
type
20°
B.T.D.C.
below
at
1 650
r/min
and
35°
B.T.D.C.
above
at 3 500 r/min
Fully
transistorized
type
20°
B.T.D.C.
below
at 1
650
r/min
and
40°
B.T.D.C.
above
at
3 500
r/min
NGK
DBEA/DR8ES-Lor
NIPPON
DENSO
X24ES-U/X24ESR-U
12V
43.2
kC
(12
Ah)/10
HR
Three-phase A.C.
generator
14.5
L
(3.2
Imp
gal)
3.0
L
(2.6
Imp
qt)
2.6 L
(2.3
Imp
qt)
..145
ml
(5.11
lmpoz)
CYLINDER
HEAD
COVER
REMOVAL
•
It
is unnecessary
to
remove
four
cover
cap
bolts
®
before
removing
cylinder
head cover
®.
Four
bolts
®
cannot
be
remove
unless
camshaft
end
caps
®
are
not
removed.
I
NSTALLATI
ON
•
Be
sure to
replace
gaskets
®
and
®
with
new
ones.
•
Fill approx.
50
ml of
engine
oil in
four
pockets
of
the
cylinder
head
before
mounting
the
head cover
on
the
cylinder
head.
•
Set two
positioning
pins
at
proper
position
and
tighten
with
long
bolts
(6
x
35mm).
• Apply
small
amount
of
SUZUKI
thread
lock
cement
on
screw
®
which
clamps
camshaft
end cap
®.
• Install
tachometer
drive gear
after
cylinder
head
cover
is
fitted
to
the
cylinder
head.
• Gasket
®
should
be
fit
that
breather
hole
side
faces
toward
front.
105mm
ELECTRI
CAL
Ignition
type
Ignition
timing
15A
*
These
specifications
are subject
to
change
without
notice.
99000-32040
I
Suzuki
Thread
lock
]
cement
TIGHTENING TORQUE
Bolt(j,®and®
9—
10
N.m
(0.9—1.0kg-rn)

5
GSX400E
ENGINE
VALVE
AND
CAMSHAFT
VALVE
TIMING
REASSEMBLY
• Apply
SUZUKI
MOLY
PASTE
lightly
with
out
break
on
camshaft
journal and
valve
stem.
•
Apply
Suzuki
thread
lock
super
“13038”
to
the
cam
sprocket
bolts(.
TIGHTENING TORQUE
(
15—20
N.m
(1.5—
2.0kg-rn)
®
8—10
N.m
(0.8—
1.0
kg-rn)
®
9—11
N.m
(0.9—1.1
kg-m)
I
ENGINE
GSX400E
6
IN.open
Ex.
close
I
N.close
Moly
paste
NOTE:
The timing
chain
is
now
riding
on
all
three sprockets.
Be
careful
not to
disturb
the crankshaft
until
four
holders
are
secured.
IN.
open
Ex.
close
V
£
Moly
paste
20th
pin
1St

5
GSX400E
ENGINE
VALVE
AND
CAMSHAFT
VALVE
TIMING
REASSEMBLY
• Apply
SUZUKI
MOLY
PASTE
lightly
with
out
break
on
camshaft
journal and
valve
stem.
•
Apply
Suzuki
thread
lock
super
“13038”
to
the
cam
sprocket
bolts(.
TIGHTENING TORQUE
(
15—20
N.m
(1.5—
2.0kg-rn)
®
8—10
N.m
(0.8—
1.0
kg-rn)
®
9—11
N.m
(0.9—1.1
kg-m)
I
ENGINE
GSX400E
6
IN.open
Ex.
close
I
N.close
Moly
paste
NOTE:
The timing
chain
is
now
riding
on
all
three sprockets.
Be
careful
not to
disturb
the crankshaft
until
four
holders
are
secured.
IN.
open
Ex.
close
V
£
Moly
paste
20th
pin
1St

ENGINE
GSX400E
8
7
GSX400E
ENGINE
CYLINDER
HEAD
CYLINDER,
PISTON
AND
RING
VALVE
GUIDE
Part
No.
Part
Name
11
1
15-49290
Valve
guide
09289-05003
Oil
seal
REASSEMBLY
•
Be
sure
to
replace
cylinder
head
gasket
®
with
new one.
•
There
are
two
different washers
)
and
)
for
cylinder
head
nuts,
so
identify
each
to use
in
the specified
place.
•
Camshaft
cap
bolt
®
has
“9”
mark
on
crown
part,
so
do
not
use
other
bolt.
TIGHTENING
TORQUE
N.m
kg-rn
)
35—40
3.5—4.0
®
8—12
0.8—1.2
(
7—11
0.7—1.1
REASSEMBLY
•
Mount
new
0-ring
ID,
gasket
()
and circlips
D.
•
Be
sure
to
apply
oil
on
cylinder
surface,
piston
sliding
part,
piston
rings
()
and
piston
pin
®.
•
Use
special
tools
when
mounting
piston
on
cylinder.
Part
No.
Part
Name
09916-74520
Piston
ring
holder
099 16-74540
Band
(bore
63
—
75
mrn)
•
Confirm
that
0-ring
ID
is
properly
installed
to
groove
of
the
lower
cylinder,
and
then
install
piston
into
the
cylinder.
ID
Q
OVERSIZE
OIL
RING
SIZE
rD