Yamaha TZ125M1 Application guide

4JT-28199-16LIT-11626-13-42
OWNER’S SERVICE MANUAL
TZ125M1/(M)

TZ125M1/(M)
OWNER’S SERVICE MANUAL
©1999 by Yamaha Motor Corporation, U.S.A.
1st Edition, August 1999
All rights reserved. Any reprinting or
unauthorized use without the written
permission of Yamaha Motor Corporation
U.S.A. is expressly prohibited.
Printed in Japan
P/N. LIT-11626-13-42
EC010000

EC020000 INTRODUCTION
Congratulations on your purchase of a Yamaha
TZ series. This model is the culmination of
Yamaha’s vast experience in the production of
pacesetting racing machines. It represents the
highest grade of craftsmanship and reliability
that have made Yamaha a leader.
This manual explains operation, inspection,
basic maintenance and tuning of your
machine. If you have any questions about this
manual or your machine, please contact your
Yamaha dealer.
NOTE:
As improvements are made on this model,
some data in this manual may become outdat-
ed. If you have any questions, please consult
your Yamaha dealer.
W
PLEASE READ THIS MANUAL CAREFULLY
AND COMPLETELY BEFORE OPERATING
THIS MACHINE. DO NOT ATTEMPT TO
OPERATE THIS MACHINE UNTIL YOU
HAVE ATTAINED A SATISFACTORY
KNOWLEDGE OF ITS CONTROLS AND
OPERATING FEATURES AND UNTIL YOU
HAVE BEEN TRAINED IN SAFE AND PROP-
ER RIDING TECHNIQUES. REGULAR
INSPECTIONS AND CAREFUL MAINTE-
NANCE, ALONG WITH GOOD RIDING
SKILLS, WILL ENSURE THAT YOU SAFELY
ENJOY THE CAPABILITIES AND THE
RELIABILITY OF THIS MACHINE.

EC030010 WARRANTY INFORMATION
This model is sold AS IS, WITHOUT ANY WARRANTIES EXPRESSED OR IMPLIED REGARD-
LESS OF THE INTENDED USE.
THE PURCHASER OF THIS MACHINE, which is intended for competition purposes, IS RESPON-
SIBLE FOR ALL COSTS, SERVICE AND/OR REPAIR.

EC040001 IMPORTANT NOTICE
THIS MACHINE IS DESIGNED STRICTLY
FOR COMPETITION USE, ONLY ON A
CLOSED COURSE. It is illegal for this
machine to be operated on any public street,
road, or highway. Off-road use on public lands
may also be illegal. Please check local regula-
tions before riding.
1. THIS MACHINE IS TO BE OPERATED
BY AN EXPERIENCED RIDER ONLY.
Do not attempt to operate this
machine at maximum power until you
are totally familiar with its character-
istics.
2. THIS MACHINE IS DESIGNED TO BE
RIDDEN BY THE OPERATOR ONLY.
Do not carry passengers on this
machine.
3. ALWAYS WEAR PROTECTIVE APPAR-
EL.
When operating this machine, always
wear an approved helmet with gog-
gles or a face shield. Also wear heavy
boots, gloves, and protective cloth-
ing. Always wear proper fitting cloth-
ing that will not be caught in any of
the moving parts or controls of the
machine.
4. ALWAYS MAINTAIN YOUR MACHINE
IN PROPER WORKING ORDER.
For safety and reliability, the machine
must be properly maintained. Always
perform the pre-operation checks
indicated in this manual. Correcting a
mechanical problem before you ride
may prevent an accident.
5. GASOLINE IS HIGHLY FLAMMABLE.
Always turn off the engine while refu-
eling. Take care to not spill any gaso-
line on the engine or exhaust system.
Never refuel in the vicinity of an open
flame, or while smoking.
&SAFETY INFORMATION

6. GASOLINE CAN CAUSE INJURY.
If you should swallow some gasoline,
inhale excess gasoline vapors, or
allow any gasoline to get into your
eyes, contact a doctor immediately. If
any gasoline spills onto your skin or
clothing, immediately wash skin
areas with soap and water, and
change your clothes.
7. ONLY OPERATE THE MACHINE IN AN
AREA WITH ADEQUATE VENTILA-
TION.
Never start the engine or let it run for
any length of time in an enclosed
area. Exhaust fumes are poisonous.
These fumes contain carbon monox-
ide, which by itself is odorless and
colorless. Carbon monoxide is a dan-
gerous gas which can cause uncon-
sciousness or can be lethal.
8. PARK THE MACHINE CAREFULLY;
TURN OFF THE ENGINE.
Always turn off the engine if you are
going to leave the machine. Do not
park the machine on a slope or soft
ground as it may fall over.
9. PROPERLY SECURE THE MACHINE
BEFORE TRANSPORTING IT.
When transporting the machine in
another vehicle, always be sure it is
properly secured and in an upright
position and that the fuel cock is in
the “OFF” position. Otherwise, fuel
may leak out of the carburetor or fuel
tank.

EC050000 TO THE NEW OWNER
This manual will provide you with a good basic
understanding of features, operation, and
basic maintenance and inspection items of this
machine. Please read this manual carefully
and completely before operating your new
machine. If you have any questions regarding
the operation or maintenance of your machine,
please consult your Yamaha dealer.
NOTE:
This manual should be considered a perma-
nent part of this machine and should remain
with it even if the machine is subsequently
sold.
EC060000 NOTICE
Some data in this manual may become outdat-
ed due to improvements made to this model in
the future. If there is any question you have
regarding this manual or your machine, please
consult your Yamaha dealer.
Weights of machines without fuel
The minimum weights for road race
machines are:
for the class 125 cc . . . . . . . . . . .minimum
70 kg (154 lb)
for the class 250 cc . . . . . . . . . . .minimum
95 kg (209 lb)
for the class 500 cc . . . . . . . . . . .minimum
131 kg (289 lb)
In modifying your machine (e.g., for weight
reduction), take note of the above limits of
weight.
EC070011
F.I.M. MACHINE WEIGHTS:

EC080000 HOW TO USE
THIS MANUAL
EC081000
PARTICULARLY IMPORTANT INFOR-
MATION
!!
The Safety Alert Symbol means ATTENTION!
BECOME ALERT! YOUR SAFETY IS
INVOLVED!
W
Failure to follow WARNING instructions could
result in severe injury or death to the machine
operator, a bystander, or a person inspecting
or repairing the machine.
CCCAUTION:
A CAUTION indicates special precautions that
must be taken to avoid damage to the
machine.
NOTE:
A NOTE provides key information to make pro-
cedures easier or clearer.
EC082000
FINDING THE REQUIRED PAGE
1. This manual consists of seven chapters;
“General Information”, “Specifications”,
“Regular inspection and adjustments”,
“Engine”, “Chassis”, “Electrical” and
“Tuning”.
2. The table of contents is at the beginning of
the manual. Look over the general layout of
the book before finding then required chap-
ter and item.
Bend the book at its edge, as shown, to find
the required fore edge symbol mark and go
to a page for required item and description.

EC083000
MANUAL FORMAT
All of the procedures in this manual are organized in a sequential, step-by-step format. The infor-
mation has been complied to provide the mechanic with an easy to read, handy reference that con-
tains comprehensive explanations of all disassembly, repair, assembly, and inspection operations.
In this revised format, the condition of a faulty component will precede an arrow symbol and the
course of action required will follow the symbol, e.g.,
•Bearings
Pitting/Damage ≥Replace.
EC084002
HOW TO READ DESCRIPTIONS
To help identify parts and clarify procedure steps, there are exploded diagrams at the start of each
removal and disassembly section.
1. An easy-to-see exploded diagram 1is provided for removal and disassembly jobs.
2. Numbers 2are given in the order of the jobs in the exploded diagram.Anumber that is enclosed
by a circle indicates a disassembly step.
3. An explanation of jobs and notes is presented in an easy-to-read way by the use of symbol marks
3. The meanings of the symbol marks are given on the next page.
4. Ajob instruction chart 4accompanies the exploded diagram, providing the order of jobs, names
of parts, notes in jobs, etc.
5. Extent of removal 5is provided in the job instruction chart to save the trouble of an unneces-
sary removal job.
6. For jobs requiring more information, the step-by-step format supplements 6are given in addi-
tion to the exploded diagram and job instruction chart.
CLUTCH
4-25
ENG
EC4A8100
CLUTCH HOUSING AND PUSH LEVER AXLE
Extend of removal: 1Clutch housing removal 2Push lever axle removal
Extend of removal Order Part name Q’ty Remarks
CLUTCH HOUSING AND
PUSH LEVER AXLE
REMOVAL
1 Nut (clutch boss) 1
2 Lock washer 1 Use special tool.
3 Clutch boss 1 Refer to “REMOVAL POINTS”.
4 Spacer 2 1
5 O-ring (small) 1
6 Clutch housing 1
7 O-ring (large) 1
8 Bearing 1
9 Spacer 1 1
10 Ball 1
11 Push rod 1
12 Bolt (seat plate) 1
13 Seat plate 1
14 Push lever axle 1
T 50 Nm (5.0 mdkg, 36 ftdlb)
T 11 Nm (1.1 mdkg, 8.0 ftdlb)
2
1
CLUTCH
4-26
EC4A3000
REMOVAL POINTS
EC483211
Clutch boss
1. Remove:
•Nut 1
•Lock washer 2
•Clutch boss 3
NOTE:
Straighten the lock washer tab and use the
clutch holding tool 4, 5to hold the clutch
boss.
Clutch holding tool:
YM-91042 . . . . . . . . . . . . . . . .44
90890-04086 . . . . . . . . . . . . .55
B
AFor USA and CDN
BExcept for USA and CDN
EC4A4000
INSPECTION
EC484100
Clutch housing and boss
1. Inspect:
•Clutch housing 1
Cracks/Wear/Damage ≥Replace.
•Clutch boss 2
Scoring/Wear/Damage ≥Replace.
EC4A4100
Clutch housing
1. Check:
•Circumferential play
Free play exists ≥Replace.
•Gear teeth a
Wear/Damage ≥Replace.
•O-ring 1
Damage ≥Replace.
EC484400
Clutch spring
1. Measure:
•Clutch spring free length a
Out of specification ≥Replace springs as
a set.
Clutch spring free length:
Standard <Limit>
36.0 mm (1.417 in) 35.0 mm (1.378 in)
{
ENG
1
6
2
4
5
3

EC085002
ILLUSTRATED SYMBOLS
(Refer to the illustration)
Illustrated symbols 1to 7are designed as
thumb tabs to indicate the chapter’s number
and content.
1General information
2Specifications
3Regular inspection and adjustments
4Engine
5Chassis
6Electrical
7Tuning
Illustrated symbols 8to ¢are used to identi-
fy the specifications appearing in the text.
8With engine mounted
9Special tool
0Filling fluid
¡Lubricant
™Tightening
£Specified value, Service limit
¢Resistance ( Ω), Voltage ( V ), Electric cur-
rent ( A )
Illustrated symbols ∞to ªin the exploded dia-
grams indicate grade of lubricant and location
of lubrication point.
∞Apply transmission oil
§Apply engine mixing oil
¶Apply molybdenum disulfide oil
•Apply lightweight lithium-soap base grease
ªApply molybdenum disulfide grease
Illustrated symbols ºto !in the exploded dia-
grams indicate where to apply a locking agent
and where to install new parts.
ºApply locking agent (LOCTITE®)
!Use new one
1
GEN
INFO
3
INSP
ADJ
5
CHAS
7
TUN
8
6
ELEC
4
ENG
2
SPEC
9
¡
£
∞
º!
•ª
¶§
¢
™
0

MEMO

EC090000
INDEX
GENERAL INFORMATION GEN
INFO 1
TUNING TUN 7
CHASSIS CHAS 5
ELECTRICAL ELEC 6
ENGINE ENG 4
REGULAR INSPECTION AND ADJUSTMENTS INSP
ADJ 3
SPECIFICATION SPEC 2

EC0A0000 CONTENTS
CHAPTER 1
GENERAL INFORMATION
DESCRIPTION. . . . . . . . . . . . . . . . . . . . . 1-1
MACHINE IDENTIFICATION . . . . . . . . . . 1-2
IMPORTANT INFOMATION . . . . . . . . . . . 1-3
CHECKING OF CONNECTION . . . . . . . . 1-5
SPECIAL TOOLS. . . . . . . . . . . . . . . . . . . 1-6
CONTROL FUNCTIONS . . . . . . . . . . . . . 1-9
FUEL AND ENGINE MIXING OIL. . . . . . 1-14
INFORMATION BEFORE
PRE-OPERATION . . . . . . . . . . . . . . . . . 1-15
STARTING AND BREAK-IN. . . . . . . . . . 1-16
TORQUE-CHECK POINTS. . . . . . . . . . . 1-19
CLEANING AND STORAGE . . . . . . . . . 1-20
CHAPTER 2
SPECIFICATIONS
GENERAL SPECIFICATIONS . . . . . . . . . 2-1
MAINTENANCE SPECIFICATIONS . . . . . 2-3
GENERAL TORQUE SPECIFICATIONS. 2-11
DEFINITION OF UNITS . . . . . . . . . . . . . 2-11
CABLE ROUTING DIAGRAM . . . . . . . . 2-12
CHAPTER 3
REGULAR INSPECTION
AND ADJUSTMENTS
MAINTENANCE INTERVALS. . . . . . . . . . 3-1
PRE-OPERATION INSPECTION AND
MAINTENANCE. . . . . . . . . . . . . . . . . . . . 3-4
LOCKING WIRE INSTALLATION GUIDE. 3-5
ENGINE. . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
CHASSIS. . . . . . . . . . . . . . . . . . . . . . . . 3-13
ELECTRICAL. . . . . . . . . . . . . . . . . . . . . 3-37

CHAPTER 4
ENGINE
COWLING, SEAT AND FUEL TANK . . . . 4-1
EXHAUST PIPE AND SILENCER . . . . . . 4-3
RADIATOR . . . . . . . . . . . . . . . . . . . . . . . 4-4
CARBURETOR AND REED VALVE. . . . . 4-7
CYLINDER HEAD,CYLINDER AND
PISTON . . . . . . . . . . . . . . . . . . . . . . . . . 4-17
CLUTCH . . . . . . . . . . . . . . . . . . . . . . . . 4-27
PRIMARY DRIVEN GEAR, PRIMARY
DRIVE GEAR AND BALANCER
SHAFT. . . . . . . . . . . . . . . . . . . . . . . . . . 4-35
SHIFT SHAFT AND OIL PUMP . . . . . . . 4-42
TRANSMISSION, SHIFT CAM AND
SHIFT FORK . . . . . . . . . . . . . . . . . . . . . 4-48
CDI MAGNETO . . . . . . . . . . . . . . . . . . . 4-58
ENGINE REMOVAL . . . . . . . . . . . . . . . . 4-61
CRANKCASE, CRANKSHAFT AND
WATER PUMP . . . . . . . . . . . . . . . . . . . . 4-65
CHAPTER 5
CHASSIS
FRONT WHEEL AND REAR WHEEL. . . . 5-1
FRONT BRAKE AND REAR BRAKE. . . . 5-9
FRONT FORK . . . . . . . . . . . . . . . . . . . . 5-25
HANDLEBAR. . . . . . . . . . . . . . . . . . . . . 5-39
STEERING. . . . . . . . . . . . . . . . . . . . . . . 5-44
SWINGARM. . . . . . . . . . . . . . . . . . . . . . 5-51
REAR SHOCK ABSORBER. . . . . . . . . . 5-58
CHAPTER 6
ELECTRICAL
ELECTRICAL COMPONENTS AND
WIRING DIAGRAM . . . . . . . . . . . . . . . . . 6-1
IGNITION SYSTEM . . . . . . . . . . . . . . . . . 6-2
SOLENOID VALVE SYSTEM. . . . . . . . . . 6-6
THERMO UNIT SYSTEM. . . . . . . . . . . . . 6-9
CHAPTER 7
TUNING
ENGINE. . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
CHASSIS. . . . . . . . . . . . . . . . . . . . . . . . 7-14

DESCRIPTION
1-1
NOTE:
•The machine you have purchased may differ
slightly from those shown in the following.
•Designs and specifications are subject to
change without notice.
GEN
INFO
EC100000
GENERAL INFORMATION
EC110000
DESCRIPTION
1Clutch lever
2“ENGINE STOP” button
3Water temperature gauge
4Front brake lever
5Throttle grip
6Radiator cap
7Fuel tank cap
8Valve joint
9Front fork
0Radiator
¡Check bolt (Transmission oil level)
™Rear brake pedal
£Steering damper
¢Fuel cock
∞Rear shock absorber
§Drive chain
¶Shift pedal
•Starter knob
ªCDI magneto
1

MACHINE IDENTIFICATION
1-2
EC120001
MACHINE IDENTIFICATION
There are two significant reasons for knowing
the serial number of your machine:
1. When ordering parts, you can give the num-
ber to your Yamaha dealer for positive iden-
tification of the model you own.
2. If your machine is stolen, the authorities will
need the number to search for and identify
your machine.
EC121001
VEHICLE IDENTIFICATION NUMBER
(For USA, CDN, AUS, NZ and E)
The vehicle identification number 1is
stamped on the right of the steering head pipe.
EC122001
FRAME SERIAL NUMBER
(Except for USA, CDN, AUS, NZ and E)
The frame serial number 1is stamped on the
right of the steering head pipe.
EC123001
ENGINE SERIAL NUMBER
The engine serial number 1is stamped into
the elevated part of the right-side of the
engine.
EC124000
MODEL LABEL
The model label 1is affixed to the frame
under the rider’s seat. This information will be
needed to order spare parts.
GEN
INFO
1

IMPORTANT INFORMATION
1-3
EC130000
IMPORTANT INFORMATION
EC131002
PREPARATION FOR REMOVALAND DISAS-
SEMBLY
1. Remove all dirt, mud, dust, and foreign
material before removal and disassembly.
2. Use proper tools and cleaning equipment.
Refer to “SPECIAL TOOLS” section.
3. When disassembling the machine, keep
mated parts together. They include gears,
cylinders, pistons, and other mated parts
that have been “mated” through normal
wear. Mated parts must be reused as an
assembly or replaced.
4. During the machine disassembly, clean all
parts and place them in trays in the order of
disassembly. This will speed up assembly
time and help assure that all parts are cor-
rectly reinstalled.
5. Keep away from fire.
GEN
INFO

IMPORTANT INFORMATION
1-4
EC132000
ALL REPLACEMENT PARTS
1. We recommend to use Yamaha genuine
parts for all replacements. Use oil and/or
grease recommended by Yamaha for
assembly and adjustment.
EC133000
GASKETS, OIL SEALS AND O-RINGS
1. All gaskets, oil seals, and O-rings should be
replaced when an engine is overhauled. All
gasket surfaces, oil seal lips, and O-rings
must be cleaned.
2. Properly oil all mating parts and bearings
during reassembly. Apply grease to the oil
seal lips.
EC134000
LOCK WASHERS/PLATES AND COTTER
PINS
1. All lock washers/plates 1and cotter pins
must be replaced when they are removed.
Lock tab(s) should be bent along the bolt or
nut flat(s) after the bolt or nut has been
properly tightened.
EC135001
BEARINGS AND OIL SEALS
1. Install the bearing(s) 1and oil seal(s) 2
with their manufacturer’s marks or numbers
facing outward. (In other words, the
stamped letters must be on the side
exposed to view.) When installing oil
seal(s), apply a light coating of light-weight
lithium base grease to the seal lip(s). Oil the
bearings liberally when installing.
CCCAUTION:
Do not use compressed air to spin the bear-
ings dry. This causes damage to the bear-
ing surfaces.
EC136000
CIRCLIPS
1. All circlips should be inspected carefully
before reassembly. Always replace piston
pin clips after one use. Replace distorted
circlips. When installing a circlip 1, make
sure that the sharp-edged corner 2is posi-
tioned opposite to the thrust 3it receives.
See the sectional view.
4Shaft
GEN
INFO

CHECKING OF CONNECTION
1-5
EC1C0001
CHECKING OF CONNECTION
Dealing with stains, rust, moisture, etc. on the
connector.
1. Disconnect:
•Connector
2. Dry each terminal with an air blower.
3. Connect and disconnect the connector two
or three times.
4. Pull the lead to check that it will not come
off.
5. If the terminal comes off, bend up the pin 1
and reinsert the terminal into the connector.
6. Connect:
•Connector
NOTE:
The two connectors “click” together.
7. Check for continuity with a tester.
NOTE:
•If there in no continuity, clean the terminals.
•Be sure to perform the steps 1 to 7 listed
above when checking the wireharness.
•For a field remedy, use a contact revitalizer
available on the market.
•Use the tester on the connector as shown.
GEN
INFO

SPECIAL TOOLS
1-6
GEN
INFO
EC140001
SPECIAL TOOLS
The proper special tools are necessary for complete and accurate tune-up and assembly. Using the
correct special tool will help prevent damage caused by the use of improper tools or improvised
techniques. The shape and part number used for the special tool differ by country, so two types are
provided. Refer to the list provided to avoid errors when placing an order.
NOTE:
•For U.S.A. and Canada, use part number starting with “YM-” or “YU-”.
•For others, use part number starting with “90890-”.
Part number Tool name / How to use Illustration
YU-01135-A, 90890-01135 Crankcase separating tool YU-01135-A 90890-01135
YM-01305, 90890-01305 Crankcase separating bolt YM-01305 90890-01305
These tools are used to split the crankcase as well
as remove the crankshaft from either case.
YM-01189, 90890-01189 Flywheel puller YM-01189 90890-01189
This tool is used to remove the flywheel magneto.
YU-01235, 90890-01235 Rotor holding tool YU-01235 90890-01235
This tool is used when loosening or tightening the
flywheel magneto securing nut.
YU-03097, 90890-01252 Dial gauge and stand YU-03097 90890-01252
YU-01256 Stand YU-01256
These tools are used to set the ignition timing.
Crankcase installing tool YU-90050 90890-01274
YU-90050, 90890-01274 Pot YU-90063 90890-01275
YU-90050, 90890-01275 Bolt 90890-01278
YU-90063, 90890-01278 Adapter
These tools are used to install the crankshaft.
YU-01304, 90890-01304 Piston pin puller YU-01304 90890-01304
This tool is used to remove the piston pin.
YU-24460-1,90890-01325 Radiator cap tester YU-24460-1 90890-01325
YU-33984, 90890-01352 Adapter YU-33984 90890-01352
These tools are used for checking the cooling system.