Yamaha ET250 User manual

FOREWORD
This service manual provides technical in-
formation on the 1980 models including its
features, differences from the 1979 models
and
new service procedure.
Please read
this manual thoroughly so that
you can have a good knowledge of the new
model and make best use of it in your sales
and after-service activities.
SERVICE DEPARTMENT
YAMAHA MOTOR CO,. LTD.
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.

Particularly important information is dis-
tinguished in
this manual by the following
notations:
NOTE:
A NOTE provides key information to make
procedures easier or cleaner.
CAUTION:
ACAUTION indicates special procedures
that must be followed to avoid change to the
machine.
WARNING:
A WARNING indicates special procedures
that must be followed to avoid injury to a
machine
operator or person inspecting or re-
pairing the machine.

·1980 ET250
CONTENTS
1. MODI·FICATIONS , ..
A. ENGINE , ...
8. DRIVE , 3
C. CHASSiS , 4
D. ELECTRICAL. , , 6
2. SERVICE 7
A. NEW SERVICE PROCEDURE 7
B. MAINTENANCE INTERVALS 10
C. SPECiFiCATIONS 12
D. SPECIAL TOOLS 17
E. WIRE ROUTING DIAGRAM 19
F. WIRING DIAGRAM 20
A. ENGINE
1. Left crank
Due to use of a new type clutch, the
crankshaft is tapered at its end to
mount the clutch.
'79 model
1. Left crank (8F3-11412-00)
. 2. Bearing (93306-30605)
3. Oil seal (93102-32161)
Interchangeability: No
(Refer to
"8. Drive, clutch.")
As a result. the bearing and oil seal in-
side diameters are changed from 32
mmto 30 mm.
'80 model
1. Left crank
(8J2-11412-00l
2.' 8earing(93306-30617)
3. Oil seal (93102-30188)
-1

1980 ET250
2. Starter
The air duct is no longer provided be-
cause there will be no problem of
overheating. Accordingly, the insert for
mounting
of the air duct on the starter
case is no longer used.
1. Air duct ...No longer used
(8G5-15471-001
2. Screw ... No longer used
(98506-050081
3. Plainwasher H' No longer used
(92906-05200)
4. Starter case
(8F3-15711-01 )
-2-
NOTE: ------------,---
The 1979 model can also be used without
installing the air duct.

B. DRIVE
Primary sheave
For better clutch operation and increased
durability, the new clutch has been adopted.
'79 model
1. Primary sheavecap complete
(8H7-17630-00l
2. Bolt
(90105-12009l
3. Washer
(90215-12084)
4. Washer
(90201-121911
5. Primary sliding sheavecomplete
(8F3-17620-00)
6. Compressionspring
(90501-55451)
7. Nut
190179-28088)
8. Washer
(90208-28003)
9. Spring set
(820-17644-00)
10. Cam
(8G5-17623-00)
11. Primary fixed sheavecomplete
(8E3-17610-00)
-3-
'80 model
1. Primary fixed sheave complete
(8H9-17610-00)
2. Primary sliding sheave
18H9-17621-00l
3. Bushing
(90389-39023)
4. Cap (8H9-17631-00l
5. 8ushing (90389-26022)
6. Bolt (97311-06025)
7. Boll(97311-06040)
B. Spring washer
(92902-06100)
9. Spider (8H9-17627-00)
10. Slide 18A7-17653-00)
11. Pin with hole
(90240-07066)
12. Plate washer
(90201-06589)
13. Weight (8H9-17632-001
14. Collar(90387-096981
Interchangeability:
1980 ET250
2
15. Collar (90387-06697)
16. Bolt IBH9-17647-00l
17. Plate washer
(90201-06053)
1B. Cotter pin
(91402-25012)
19. Compression spring
(90501·55345)
20. Cam (BJ2-17623-00)
21. Hexagon bolt
(90101-06440\
22. Self locking nut
(95601-06100)
23. Platewasher
(90201-06727)
24. Platewasher
(90201-09728l
25. Platewasher
(90201-06750)
No

1980ET250
C. CHASSIS
1. Frame
(8H7-21910-00 --+ 8K3-21910-00)
oFor better durability of the frame, the
engine hood material
IS changed from
aluminum to steel plate (Black coat-
ing).
oThe drive guard bracket is welded to
the hood for easy assembling.
oThe front part of the frame is painted
black as part of the new
1980 model
design.
Attl....Steel plate (blackl
Welded drive guard bracket
8K3-2191 0-00 can be used on both
79 and '80 models.
8H7-21910-00 can not be used on
'80 model.
2. Steering gate
(8H7 -23871-00 __ 8 K3-23871-00)
For easy assembling and maintenance,
the drive guard bracket is welded to the
steering gate.
Interchangeability: Yes
4
(The previous model's steering gate (8H7-
23871-00 is interchangeable, as a set
with the drive guard bracket (8 F3-77316-
01L with the new steering gate).
NOTE: ------------
Due to modifications in 1, and 2. above, the
1979 model's drive guard bracket 1 (8G5-
77315-00) and bracket 2 (8F3-77316-01)
are no longer used.
3. Drive guard
(8F3-77311-01 --+ 8G8-77311-00)
Due to use of the new type clutch, the
shape
of the drive guard is changed.
'79 model
'80 model
8G8-77311-00 can be used on both 79
and '80 models.
8F3-77311-01 can not be used on '80
model.

4. Throttle
To keep the throttle cable end, which is
held by
the throttle lever, from contact-
Lever(8G8-421:38-00
Lever (8J5-42138-00) and collar (9038,7-
19aOET250
ing the throttle grip, acollar is mounted
and the lever is properly curved.
Collar (90387 ·22726)
Lever (8G8-42138-00) can not be used
5. Tune-up label
(8K3-77743-00)
As an aid to service, a tune-up label is
attached to the intake silencer.
EI250 (BKal SPECIFIKATIONER
1. BENSIN
2. MOTOROLJA
3. TANDSTIFT
4. ELEKTRODEAVSTAND
5. TANDINSTALLNING
6. LAoFART (BRANSLEl JUSTERINGSSKRUV
7. TOMGANGSVARVTAL
8. BRANSLENIVA
9. KEDJEHUS OWEVOLYM OCH VISKOSITET
450 cc, GEAROLJA
10. VARITORAVSTAND
11 VARIATOR SIDOFORSKJUTNING
12. MATTSPANNING IS;RlJd~~~~~
• FOR YTTERLIGARE INFORMATION SE l~
DENNA MODELL.
• SPECIFIKATIONER!<ANANDRAS UTAN MEODELANOE.
-5

1980 ET250
D. ELECTRICAL
1. Main switch
(8F3-82508-20 ----j. 8J5-82508-21)
For additional safety, the headlight and
'79 model
tailliqht circuits are changed so that
these lights are kept turned on as long
as the engine is in operation.
'80 model
Yellow Bille
ON ON/LIGHT
LIGHT
Gray
Black/White
Black
Interchangeability: No
2. Wire harness
(8H7-82590-20 -- 8K3-82590-20)
For additional safety, the headlight and
taillight circuits are changed so
that
these lights are kept turned on as long
as the engine is in operation.
(Refer to
"2-E Circuit Diagram.")
Interchangeability: No
-6-
3. Engine stop switch
(8E3-83976-01 )
For additional safety, the engine stop
switch is added.

1980 ET250
2. SERVICE
A. NEW SERVICE PROCEDURE
(New service procedure applied to the 1980
ET250)
b. Remove the primary sheave assembly,
using the primary fixed sheave puller
bolt and primary sheave holding tool.
Tool No.
90890-01879
Tool name
2. Disassembly
a. Separate the sliding sheave assembly
from the fixed sheave by rotating the
sliding sheave counterclockwise. .
Sheave sub-assembly tool
b. Install the sheave sub-assembly tool to
the primary sheave.
Tool No.
Tool No.
90890-01880
Tool name
Sheave holder
Tool name
Primary shave
1. Removal
a. Remove the primary sheave mounting
bolt, using the sheave holder.
Primary fixed sheave puller
bolt 1M18 P1.5)
90890-01881
1. Sheave sub-assembly tool
1 Primary fixed sheave puller
bolt
c. Loosen the six bolts securing the
primary sheave cap and sliding sheave.
d. Remove the sheave subassembly tool.
The primary sheave cap and sliding
sheave cap now be disassembled.
3. Inspection
a. Check the tapered ends of the crank-
shaft and primary fixed sheave for
scratches. If scratched unduly, replace.
If scratches are minor, burnish with
emery cloth.
b. Check the primary sheave cap bushing
and sliding sheave bushing for wear. If
beyond tolerance, replace the bushing.
7

1980 ET250
NOTE: ------------
If bushing is installed tightly, remove the bu-
shing using
the bushing tool.
.~
Bushing clearance, limit
Small bushing Large bushing
Inside
0.25 mm (0.01 in)
0.25 mm (0.01 in)
Outside
0.25 mm (O.Ol in)
0.25 mm (0.01 in)
.' Tool name Tool No.
... X Free from grease
... Greasing point
for free
90890-01877
Bushing tool
Checkthtrspider and rollerfof'slllooth
movement and wear.
e. Check both sheaves for warping. If
warped, replace.
4. Reassembly
.a. Oil the points shown in the illustration.
Do
not apply the grease on the portion
of X mark. For other parts. greasing is
unnecessary.
CAUTION: -----'------..,
If the U -nut or cotter pin is removed for.
the greasing, replace it with ne\iV one .
1 Bushing tool
-8