Yamaha SRX440 1980 User manual

FOREWORD
This Service Manual has been written to acquaint the mechanic with the
disassembly. reassembly. maintenance. and troubleshooting procedures re-
quired to provide
optimum performance and longevity of the machine.
The information herein should be closely studied to avoid unnecessary re-
pairs and to provide the
owner with a sound. safe. dependable machine.
NOTE:------------ _
The Research and Engineering Departments of Yamaha are continually
striving to further perfect all models. Improvements and modifications are
therefore inevitable.
In light of this fact. all specifications within this manual are subject to
change
without notice. Information regarding changes is forwarded to all
Authorized Yamaha Dealers as soon as available.
YAMAHA MOTOR CO" LTD.
SERVICE DEPARTMENT
Particularly important information is distinguished in this manual by the fol-
lowing notations:
NOTE: A NOTE provides key information to make procedures
easier or cleaner.
CAUTION: ACAUTION indicates special procedures that must be fol-
lowed to avoid damage to the machine.
WARNING: A WARNING indicates special procedures that must be fol-
lowed to avoid injury to a machine operator or person in-
specting or repairing the machine.
1980 SRX440

SECTION INDEX
GENERAL
ENGINE
COOLING SYSTEM
CARBURETION
POWER TRAIN
CHASSIS
.~
ELECTRICAL
APPENDIX

CHAPTER 1. GENERAL
1-1. EXTERNALVIEW. 1-2
1-2. MACHINE IDENTIFiCATION 1-3
A. Frame serial number. 1-3
B. Engine serial number 1-3
1-3. MAINTENANCE INTERVALS CHARTS 1-4
A. Periodic maintenance 1-4
B. Lubrication intervals 1-5
1-4. HIGH ALTITUDE TUNING 1-6
1980 SRX440

1980 SRX440
1-1. EXTERNAL VIEW
CHAPTER 1. GENERAL
1-2

1980 SRX440
1-2. MACHINE IDENTIFICATION
A. Frame serial number
The frame serial number is located on the
righthand side of frame (just
below the front
of seat). The first three digits identify the
model. This is
followed by a dash. The re-
maining digits
identify the production
number of the unit.
B.
Engine serial number
The engine serial number is located on the
right-hand side of crankcase cover. The pre-
fix indicates engine
type and displacement.
The prefix is
followed by a dash and the SEl-
rial number. Normally both frame and engine
serial numbers are identical; however, on
occasion they may be
two or three numbers
off.
Frame starting serial number 8K6-015101 Engine starting serial number
1-3. MAINTENANCE INTERVALS CHARTS
A. Periodic maintenance
(Use this just as guide only. Certain conditions may require more frequent inspection of compo-
nents.)
Every
..
20 hrs. or 40 hrs. or 80 hrs. or
When
Seasonally
Check point
400km aOOkm 1,600 km necessary
(250mi) (500 mil
(1.000mi)
ENGINE:
Tightness of bolts and nuts
00
Bends, cracks and wear
00
Abnormal noise 00
Loose connection and breaks of fuel and pulse pipes 00
Loose connection and breaks of oil pipes
00
Loose connection and breaks of oil delivery pipe
00
Manual rope starter system 00
Carburetor
•Operation of starter
jet
00
•
Mixing adjuster (pilot screw) 0 0
•
Idling speed adjustment
0 0
•
Throttle valve synchronization 00
Operation and adjustment of oil pump 00
Ignition timing
0
Engine compressions 00
Cylinder head/exhaust pipe decarbonize
0
Spark plug condition, gap and cleaning
00
Tightening of the cylinder head •• 0
"'. Retighten every 10 hours from the first use.
1-3

1980 SRX440
Every
Check point
20 hrs. or
40 hrs. or 80 hrs. or
When
Seasonally
400km
800 km 1,600 km necessary
(250mi) (500mi)
(1.000 mil
Coolant leakage
0 0
Operation of thermostat
00
Operation of water pump
00
Water pump belt tension. damage
0 0
Coolant level 0 0
.
DRIVE
.
Tightness of bolts and nuts
00
Wear on slide runners
00
Primary drive system
0 0
V-belt
0 0
Secondary drive system
00
Sheave distance
00
Sheave offset
0 0
Brake pad wear
0 0
Brake operation and adjustment
0 0
Guide wheel rubber
0 0
Wear of drive track wheel sprocket 0 0
Drive track adjustment
00
Breaks in drive track 00
Bends in front and rear axles
0 0
Checking of lock washers
0 0
Drive chain adjustment
00
-mwe cnam 6if ever
<:Y 0
BODY'
Tightness of bolts and nuts
00;=
Bends and cracks 00
Welded riveted. joints
00
Ski adjustment
00
Ski runner wear
00
Breaks in fuel tank 00
Cleaning of fuel tank 0
Fuel filter
0
Loose connection and breaks in fuel pipe 00
Breaks in oil tank
00
Oilfifter
0
ElECTRICAL: .
Wear, breakage of wire covering 00
Breaks in high-tension cord_
00
Voltage regulator working voltage 0
Operation of engine stop switch
00
Operation of tether switch
00
Headlight 00
Taillight 00
Brake light
00
Oil caution light
00
1-4

B. Lubrication intervals
1980 SRX440
Every
Check point
20 hrs. or 40 hrs. or 80 hrs. or
When
Seasonally Oil/Grease
40Qkm 800 km 1,600 km necessary Brand
name
(250 mil (500 mil {1.000mil
ENGINE:
Starter case
0
Speedometer drive housing 00.
.
Water pump bearing and oil 00
Aeroshell grease #7 A or
seal Esso Beacon
325 grease
Oil
pump control box 0 0
Pump drive cover 0 0
Oil in the oil tank 0
YAMALUBE 2-cycle oil
DRIVE:
Primary sheave weight
00
and roller pins
Molybdenum disulfide
Secondary shaft and 0
snowmobile grease
Sliding sheave 0
Front axle housing 0 0
Shaft 1 and shaft 200
light all-purpose grease
{Slide rail}
Drive chain oil 0 0 Gear oil API
"Gl-3"
replacement
SAE#750r#80
BODY:
Steering column lower
0 0
Light all-purpose grease
bearing
Steering column upper 0 0
Motor oil
Steerina links 0
Ski column 0 0
Light all-purpose grease
Ski
wear plate 0 0
Ski retaining pin 0 0
Light all-purpose grease
Brake
wire end stopper 00Esso Beacon
325 grease
and brake lever
1-5

1980 SRX440
3. Using the flywheel puller, remove the
flywheel assembly.
F.
Oil pump
1. Remove the oil delivery pipes.
2. Remove
the bolts and pump drive case.
E.
Primary sheave
Refer to "5-1-8. Primary sheave"
Tool No.
90890-01235 Rotor holding tool
Tool name
1. Rotor holding tool
No. Tool name
Drive handle
Tool No.
90890-01817
NOTE: -----------
The oil pump can be removed as an
assembl
to ether with the um drive
4Flywheel puller screw
(q\8 X 80 mm)
90890-01806
cover. If it is hand to remove the pump drive
case.
tap it with asoft-faced hammer.
3. Remove the Phillips-head screw, and
remove
the coil plate.
NOTE:------------
When removing the flywheel, the key must
be removed from the crankshaft.
Take care so
that it is not lost.
CAUTION:---------,
The oil pump must not be disassembled,
because the oil pump is a precision
work.
3. Remove the oil pump cap and pump
wire.
4. Remove the oil pump assembly.
G.
Engine disassembly.
1. Remove the thermostat case and joint.
90890-01804
Flywheel puller
attachment
5
2-4
L

1980 SRX440
:~
1\10I E:
For thermostat inspection. refer to 3-5
thermostat.
2. Remove the intake manifold.
3. Remove the exhaust pipe assembly.
4. Remove the cylinder head
holding nuts.
cylinder head. gasket and
a-ring.
NOTE: -------------
Loosen spark plugs before removing cylinder
head.
5. Remove the cylinder and cylinder base
gasket.
6. Remove piston pin
clip from piston.
NOTE: -------------
Before removing the piston pin clip. cover
the crankcase with a clean rag to prevent the
clip
from accidentally falling into the
crankcase.
7. Push piston pin
from opposite side. then
pull out. Protect pin with rag.
NOTE:-------------
Before moving piston pin. deburr clip groove
and pin hole area.
2·5
8. Remove engine bracket.
9. Remove crankcase holding bolts
.. Each
bolt position is numbered, Start with the
largest number for disassembly. Loosen
each
bolt 1/4 turns and proceed to the
next.
10.
Split crankcase by lightly striking the
upper and lower crankcases.
11. Remove crankshaft by
tapping the shaft
with your hands.
2-2. INSPECTION. REASSEMBLY AND
ADJUSTMENT
A. Engine components
1. Crankcase
a.
Thoroughly wash the case halves in
mild solvent.
b. Clean gasket
mating surfaces and
crankcase
mating surfaces thoroughly.
c. Visually inspect case halves for any
cracks. road damage. etc.
d. Check oil delivery passages in transfer
ports
for signs of blockage.
2. Bearing and oil seal inspection
a.
After cleaning and lubricating bearings.
rotate
outer race with afinger. If rough
spots are noticed. replace
the bearing.

1980 SRX440
b. Check oil seal lips for damage and wear.
Replace as required.
3. Bearing and oil seal installation
a.
When installing or removing left crank
oil seal and bearing. remove the pump
drive gear and install
new drive gear.
Crank bearing Yamalube 2-cycle oil
Crankshaft oil seal Low temperature grease
lip (Esso Beacon
325 or
Aerosheli grease #7AI
4. Crankshaft inspection
a. Check connection rod axial play at small
end (to determine.
the amount of wear
of crank pin and bearing at big end).
If small end play exceeds tolerance. dis-
assemble
the crankshaft. check con-
necting rod. crank pin and big end bear-
mg.
Replace defective parts. Play after reas-
sembly should be
within specification.
Rod axial play:
Maximum 2.0 mm (0.079 in)
Rod side clearance
b. Check the connecting rod side clear-
ance at big end.
If axial play exceeds tolerance. disas-
semble
the crankshaft and replace any
worn parts. Big end axial play should be
within specification.
CAUTlON:---------...,
When removing pump drive gear. re-
place it with new one.
b. Install bearing(s)
with their manufac-
turer's marks or. numbers facing
out-
ward. (In other words. the stamped let-
ters
must be on the exposed-
to-view-side.)
c. Install oil sealts) with their manufac-
turer's marks or numbers facing
out-
ward.
d. When installing bearing(s) or oil seatts).
apply the specified lubrication.
2-6
Minimum
0.25 mm (0.010 inl
Maximum
0.75 mm 10.030 in)

1980 SRX440
Deflection tolerance
Left side Center Center Right side
(left) (right)
0.03 mm 0.04mm 0.04mm
0.05 mm
(0.0012 in)
(0.0016 in) 10.0016 in) 10.0020 in)
FWD
<>
c. Check crankshaft assembly runout
(misalignment of crankshaft parts).
Dial gauge readings should be
within
specification.
Correct any misalignment by tapping
the flywheel
with a brass hammer an-
d/or by using a wedge.
80mm
~
1. Knock pin
2. Sealing surface 3.
Upper case
4.
Aligning mark
5. Crankshaftinstallation
a. Set the circlip on crank bearing as il-
lustrated. (The primary sheave side.)
CAUTION :--~-----'----,
The oil seal lip must fit into the
crankcase groove,
UPPER CASE
I
o
FWD
<>
CD
b. Install the crankshaft assembly with oil
seal, align the bearing punch marks with
the crankcase lower and upper mating
surfaces.
c. Set the pins of bearing and labyrinth
seal in pin holes of crankcase upper by
moving the bearings and labyrinth seal.
1. Circlip
LOWER CASE
2. Sealing surface 3. Knock-pin
6. Crankcase installation
a. Apply YAMAHA BOND #4 to the mat-
ing surfaces of both case halves.
Apply thoroughly over all mating sur-
faces.
b. Set the crankcase half onto lower case
half. Install the crankcase holding bolts.
Each bolt position is numbered. Tighten
all crankcase holding bolts gradually in
the order of the numbers marked on
crankcase.
2-7

8. Piston pin and bearing inspection
a. Check the pin for signs of wear. If any
wear is evident. replace pin and bearing.
1980 SRX440
Tightening torque:
First:
10 Nm (1.0 m-kg)
Final: 22 Nm (2.2 m-kg)
Tightening torque:
40 Nm (4.0 m-kg)
.
c. After reassembly, apply aliberal coating
of two-stroke oil to the crank pin, bear-
ing and
into each crankshaft bearing oil
delivery hole.
d. Check crankshaft
for freedom of move-
ment.
7. Engine bracket
installation
Install the engine brackets in the correct
position.
2-8
b. Check the pin and bearing for signs of
heat discoloration. If excessive (indenta-
tion on pin, etc.). replace pin and bear-
In.
c. Check the bearing cage for excessive
wear or damage. Check the rollers for
signs of flat spots. If such wear is found,
replace pin and bearing.
d.
Apply a light film of oil to pin and bear-
ing surfaces. Install
them in connecting
rod small end to
inspect for wear. Check
for play. There should be no noticeable
vertical play. If play exists, check con-
necting rod small end for wear. Replace
pin,
connecting rod and/or bearing, as
required.

1980 SRX440
Ring end gap free:
Approx.
7.0 mm (0.28 in)
Piston clearance:
Minimum " .. 0.065 mm (0.0026 in)
Maximum 0.070 mm (0.0028 in)
e. Wash piston in solvent and
wipe dry.
f. Measure
the outside diameter of the
piston at the piston skirt.
Measurement should. be made at a
point 10 mm (0.5 in) above the bot-
tom edge of the piston. Place the
micrometer at right angles to the piston
pin.
Piston maximum diameter subtracted
from
minimum cylinder diameter gives
1. 10 mm (0.5 in)
10. Piston ring inspection
a. Check rings for scoringlany severe
scratches are noticed, replace ring set.
b. Measure ring end gap in free position. If
beyond tolerance, replace ring set.
-----nrme-cylindel tbtblelallce 01 bOle to
next oversize and fit oversize piston.
c. Carefully remove carbon deposits from
ring grooves
with filed end of ring.
d. Remove score marks and lacquer de-
posits
from sides of piston using 600 ~
800 grit wet sandpaper. Sand in a cris-
scross pattern. Do
not sand excessively.
e. The piston pin should have no notice-
able free play in
the piston. If the piston
pin is loose, replace
the pin and/or
piston.
9. Piston inspection
a. Remove piston rings.
b. Remove carbon deposits from piston
crown.
2-9

1980 SRX440
NOTE:------------
Take care during installation to avoid damag-
ing the piston skirts against
the crankcase as
the cylinder is installed.
12. Cylinder inspection
CAUTION: --'---------...,
This model has a hard chromed cylinder
bore. which cannot be honed or bored.
c. Push the ring into the bore and check
end gap clearance
with afeeler gauge.
If beyond tolerance. replace ring set.
Ring end gap. installed:
Minimum:
0.35 mm (0.014 in)
Maximum:
0.55 mm (0.022 in)
a. Remove
the carbon deposits from ex-
haust port.
b. Remove the any obstructions from the
coolant passages.
c. Check cylinder. The cylinder inner wall
is plated
with hard chrome.
Check the edge of each
port and upper
area of the cylinder bore
for peeling-off
of chrome. If the chrome peeling is a
negligeable
amount. the cylinder may
be used.
Smooth out the edge of the
chrome
with #400 riLsandpaper to
prevent
the ring edge from catching the
edge of the chrome. But if the peeling is
present to a considerable degree. the
cylinder should be replaced.
NOTE: ------------
If the cylinder wall has a large amount of
scuffing. check each piston ring for defects.
and replace it if necessary.
11. Piston installation
a. Install the piston ring as illustrated.
b. During reassembly. coat
the piston ring
grooves. piston skirt areas. piston pin.
and bearing
with two-stroke engine oil.
c. Install
new piston pin clips and make
sure
they are full-seated in their grooves.
d. Check cylinder bore. Using acylinder
gauge. set to standard bore size.
measure
the cylinder. Measure at six
points; at
top. center and bottom.
Compare with piston measurements. If
over tolerance. replace piston or
cylinder as required.
2-10
3. Piston ring
2. Piston bottom
1. Piston head

1980 SRX440
2/~'
,-------- ~/
----------
3
e. Clean cylinder in solvent, then wash
with hot soapy water. Dry. Coat walls
with light oil film.
13. Cylinder installation
a. Install a
new cylinder base gasket.
bInstall cylinder
with one hand while
c. Remove any obstructions from the coo-
lant passages.
15, Cylinder head installation
Install cylinder head gasket, D-ring and
cyiinder head.
Working in a crisscross
pattern, tighten head nuts in two steps.
compressing piston rings
with other
Tightening torque
hand. First 20 Nm 12.0m-kg)
10 mm nut
.Final 30 Nm 13.0m-kq)
I~V II:;
First
20 Nm 12.0 m-kq)
Makesuretnerin gs aIeproperlvposttionad, 8mm nut
.. ,"" Final 25 Nm 12.5 m-kg)
14. Cylinder head inspection
a. Remove spark plug.
b. Using arounded scraper, remove
carbon deposits from
combustion
chamber. Take care to avoid damaging
spark plug threads. Do
not use a sharp
instrument.
Avoid scratching the al-
uminum.
2-11
NOTE: ------------
When the cylinder head is installed on the
cylinder, the D-ring may easily fall off the
cylinder. 'Itis advisable, therefore, to coat the
D-ring groove sparingly with grease before
this procedure.
16. Intake'manifold installation
a. Clean the
mating surfaces of cylinder
and intake manifold.
b. Coat the mating surfaces of cylinder and
intake manifold with YAMAHA BDN D
#4 and install
new intake manifold gas-
kets.

1980 SRX440
c. Install the intake manifold.
Tightening torque:
15 Nm (1.5 m-kg)
c. Measure the gap with the thickness
gauge
between the raised boss on the
pump adjust pulley and the adjust plate.
1. Adjust plate
2. Adjust pulley
3.
Minimum pump stroke
case Jam.
Minimum pump stroke:
Tightening torque:
0.20 ~ 0.25 mm
7 Nm (0.7 m-kg)
(0.0079 ~ 0.0098 in)
(}-+f clearance is not correct;-remove-the
18. Thermostat case and joint installation
Clean the mating surfaces of cylinder
head and
thermostat case/joint.
Install the new gasket and thermostat
/' . t
Tightening torque:
23 Nm (2.3 m-kg)
17. Exhaust pipe installation
Remove the carbon deposits from ex-
haust pipe. Inspect
the exhaust gasket
for
damage and replace it as required.
Install
the exhaust pipe with gasket.
B.
Oil pump
1. Minimum pump stroke checking and ad-
justment.
Normally the checking the adjustment
of the pump stroke are not required. but
if any sign of trouble resulting from an
incorrect minimum pump stroke is
noticed (e.g.. excessive engine oil con-
sumption or engine seizure). proceed as
follows:
a. Remove the oil pump assembly from
the engine.
b. Turn
the oil pump worm Wheel until the
pump plunger moves fully out and away
from the pump body to its outermost
limit.
adjust plate lock nut and the adjust
plate.
e. Remove or add an
adjust shim as re-
quired.
1. Adjust shim
f. Reinstall adjust plate and lock nut.
Tighten the lock nut. Re-measure gap.
Repeat procedure as required.
2. Oil
pump drive case installation
Coat the pump drive gear with grease.
And install the pump drive case.
2-12

1980 SRX440
Recommended grease:
Low temperature grease
(Esso Beacon
325 or Aeroshell grease
#7A)
Pump case tightening torque:
10Nm(1.0m-kg)
3. Install pump wire, pump case and oil de-
livery pipe.
CAUTION:---------...,
Before installing pump wire and pump
case, apply grease to the pump pulley
thoroughly.
Recommended grease:
Low temperature grease
(Esso Beacon
325 or Aeroshell
grease
#7A)
1. Bleed screw
2) Keep the oil running out until air bub-
bles disappear.
3)
When air bubbles are expelled com-
pletely, tighten the bleed screw.
2-13
NOTE:--~-------
Check the bleed screw gasket. and if damag-
ed. replace
with a new one.
b. Bleeding
the pump distributor and/or
delivery pipe.
1)
Start the engine.
2) Pull the pump
wire all the way out to
set the pump stroke to amaximum.
1. Pull
2. 1'00iipvvile
NOTE:
It is difficult to bleed the distributor com-
o pletely with the pump stroke at a minimum,
and therefore the pump stroke should be set
to a maximum.
3) Keep the engine running at about 2,000
r/min for two minutes or so, and both
distributor and delivery pipe can be
completely bled.
5. Cable
adjustment (After remounting
engine)
a.
Adjust throttle cable free play.
(See
4-1-A. Carburetor tuning)
b. Pull the oil
pump cable outer tube
toward the oil pump and adjust the gap
between
the adjuster and the outer tube
to specification.
Play:
23 ±1 mm (0.91 ± 0.04 in)
c.
After adjusting, don't forget to tighten
the lock nut.

1980 SRX440
1. Play
2. Adjuster
3. Lock nut
C. Primary sheave
Refer to "5-1 -B. Primary sheave".
D. Flywheel magento
(For inspection. refer to '7 -1-G. Pulser and
charge coil
test" and "7-2-C. Lighting
circuit test'")
1. Install woodruff key.
------'Tln-sfilTI-f1ywheeTbase:··
Flywheel base tightening torque:
. 6 Nm (0.6 m-kg)
Tightening torque:
10 Nm (1.0 m-kg)
E,
Water pump
NOTE: -------------
For inspection, refer to "3-4 Water pump".
1. Install the water pump assembly tem-
porarily.
2. Install the drive
water pump pulley with
water pump belt.
3. Install flywheel using
rotor holding tool.
NOTE: --_--- _
Make sure woodruff key is properly seated in
keyway of crankshaft. Carefully install fly-
wheel
while taking care so it aligns with
woodruff key.
Tool name
Rotor holding tool
Tool No.
..90890-01235
3. Install the starter pulley using rotor
holding tool.
Flywheel
nut torque:
73 Nm (7.3 m-kg)
.4. Adjust ignition timing.
CAUTION: -- ..... -------.
Whenever the flywheel magneto is re-
moved, ignition timing must be reset.
(Refer to 7-1-C. Ignition timing)
. .5. Install the crankcase cover.
2-14
Tool name
Rotor holding
tool
Tightening torque:
15 Nm (1.5 m-kg)
.
Tool No.
90890-01235