Yamaha DT125RE 2005 User manual

SERVICE MANUAL
DT125RE 1D01-AE1
DT125X
2005

DT125RE/X
1D01-1D02/2C81
SERVICE MANUAL
© 2005 Yamaha Motor España, S.A.
1st Edition, January 2005
All rights reserved. Any reprinting or
unauthorized use without the written
permission of Yamaha Motor España, S.A.
is expressly prohibited.
Printed in Spain.
EAS00001

EAS00002
NOTICE
This manual was produced by the Yamaha Motor España S.A. primarily for use by Yamaha dealers
and their qualified mechanics. It is not possible to include all the knowledge of a mechanic in one
manual. Therefore, anyone who uses this book to perform maintenance and repairs on Yamaha
vehicles should have a basic understanding of mechanics and the techniques to repair these types
of vehicles. Repair and maintenance work attempted by anyone without this knowledge is likely to
render the vehicle unsafe and unfit for use.
Yamaha Motor España S.A is continually striving to improve all of its models. Modifications and sig-
nificant changes in specifications or procedures will be forwarded to all authorized Yamaha dealers
and will appear in future editions of this manual where applicable.
NOTE:
Designs and specifications are subject to change without notice.
TECHNICAL PUBLICATIONS
YAMAHA MOTOR ESPAÑA, S.A.
EAS00004
IMPORTANT MANUAL INFORMATION
Particularly important information is distinguished in this manual by the following.
The Safety Alert Symbol means ATTENTION! BECOME ALERT!
YOUR SAFETY IS INVOLVED!
Failure to follow WARNING instructions could result in severe injury
or death to the motorcycle operator, a bystander or a person chec-
king or repairing the motorcycle.
A CAUTION indicates special precautions that must be taken to
avoid damage to the motorcycle.
A NOTE provides key information to make procedures easier or cle-
arer.
tt
ssWARNING
CAUTION
NOTE :

EAS00007
HOW TO USE THIS MANUAL
This manual is intended as a handy, easy-to-read reference book for the mechanic. Comprehensive
explanations of all installation, removal, disassembly, assembly, repair and check procedures are
laid out with the individual steps in sequential order.
The manual is divided into chapters. An abbreviation and symbol in the upper right cor-
ner of each page indicate the current chapter.
Refer to “SYMBOLS”.
Each chapter is divided into sections. The current section title is shown at the top of each
page, except in Chapter 3 (“PERIODIC CHECKS AND ADJUSTMENTS”), where the sub-
section title(s) appears.
Sub-section titles appear in smaller print than the section title.
To help identify parts and clarify procedure steps, there are exploded diagrams at the start
of each removal and disassembly section.
Numbers are given in the order of the jobs in the exploded diagram. A circled number indi-
cates a disassembly step.
Symbols indicate parts to be lubricated or replaced.
Refer to “SYMBOLS”.
A job instruction chart accompanies the exploded diagram, providing the order of jobs,
names of parts, notes in jobs, etc.
Jobs requiring more information (such as special tools and technical data) are described
sequentially.

EAS00008
SYMBOLS
The following symbols are not relevant to
every vehicle.
Symbols to indicate the subject of each
chapter.
General information
Specifications
Periodic checks and adjustments
Chassis
Engine
Cooling system
Carburetor(s)
Electrical system
Troubleshooting
Symbols 10 to 17 indicate the following.
10 Serviceable with engine mounted
11 Filling fluid
12 Lubricant
13 Special tool
14 Tightening torque
15 Wear limit, clearance
16 Engine speed
17 Electrical data
Symbols 18 to 23 in the exploded diagrams
indicate the types of lubricants and lubrica-
tion points.
18 Engine oil
19 Gear oil
20 Molybdenum-disulfide oil
21 Wheel-bearing grease
22 Lithium-soap- based grease
23 Molybdenum-disulfide grease
Symbols 24 to 25 in the exploded diagrams
indicate the following.
24 Apply locking agent (LOCTITE®)
25 Replace the part
CHK
ADJ
ENG
CARB
TRBL
SHTG
SPEC
CHAS
COOL
ELEC
GEN
INFO
New





11
13
16
18
21
24




10
12
15 17
25
20
23
19
22
14

SPEC 2
SPECIFICATIONS
CHK
ADJ 3
PERIODIC CHECKS AND
ADJUSTMENTS
CHAS 4
CHASSIS
ENG 5
ENGINE
COOL 6
COOLING SYSTEM
CARB 7
CARBURETOR
ELEC 8
ELECTRICAL SYSTEM
EAS00010
TABLE OF CONTENTS
TRBL
SHTG 9
TROUBLESHOOTING
GENERAL INFORMATION GEN
INFO 1

GEN
INFO

1

GEN
INFO
CHAPTER 1
GENERAL INFORMATION
MOTORCYCLE IDENTIFICATION ……………………………………………1-1
FRAME SERIAL NUMBER ……………………………………………………1-1
ENGINE SERIAL NUMBER……………………………………………………1-1
IMPORTANT INFORMATION …………………………………………………1-2
PREPARATION FOR REMOVAL ……………………………………………1-2
ALL REPLACEMENT PARTS …………………………………………………1-2
GASKETS, OIL SEALS AND O-RINGS ……………………………………1-2
LOCK WASHERS/PLATES AND COTTER PINS……………………………1-2
BEARINGS AND OIL SEALS …………………………………………………1-3
CIRCLIP …………………………………………………………………………1-3
CHECKING THE CONNECTIONS……………………………………………1-4
SPECIAL TOOLS …………………………………………………………………1-5

GEN
INFO
MOTORCYCLE IDENTIFICATIONS
1-1
EAS00014
GENERAL INFORMATION
MOTORCYCLE IDENTIFICATION
FRAME SERIAL NUMBER
The frame IDENTIFICATION number is
stamped onto the steering head pipe.
NOTE:
The frame serial number is used to identify the
motorcycle and therefore it can be used for the
enrollment in the face of the competent autho-
rity.
ENGINE SERIAL NUMBER
The engine serial number is stamped onto
the left side of the crankcase.
NOTE:
The first three digits of this number identifies
“the model; the other digits indicate the num-
ber” of production of the unit.
NOTE:
Design and specifications may change without
notice.



GEN
INFO
IMPORTANT INFORMATION
1-2
IMPORTANT INFORMATION
PREPARATION FOR REMOVAL AND
DISASSEMBLY
1. Before removal and disassembly, remove all
dirt, mud, dust and foreign material.
2. Use only the proper tools and cleaning
equipment.
Refer to the “SPECIAL TOOLS”.
3. When disassembling, always keep mated
parts together. This includes gears, cylin-
ders, pistons and other parts that have
been “mated” through normal wear. Mated
parts must always be reused or replaced as
an assembly.
4. During disassembly, clean all of the parts
and place them in trays in the order of
disassembly. This will speed up assembly
and allow for the correct installation of all
parts.
5. Keep all parts away from any source of fire.
EAS00021
REPLACEMENT PARTS
Use only genuine Yamaha parts for all replace-
ments. Use oil and grease recommended by
Yamaha for all lubrication jobs. Other brands
may be similar in function and appearance, but
inferior in quality.
EAS00022
GASKETS, OIL SEALS AND O-RINGS
1. When overhauling the engine, replace all
gaskets, seals and O-rings. All gasket sur-
faces, oil seal lips and O-rings must be cle-
aned.
2. During reassembly, properly oil all mating
parts and bearings and lubricate the oil seal
lips with grease.

GEN
INFO
IMPORTANT INFORMATION
1-3
EAS00024
BEARINGS AND OIL SEALS
Install bearings and oil seals so that the manu-
facturer’s marks or numbers are visible. When
installing oil seals, lubricate the oil seal lips
with a light coat of lithium-soap-based grease.
Oil bearings liberally when installing, if appro-
priate.
Oil seal
CAUTION
Do not spin the bearing with compressed
air because this will damage the bearing
surfaces.
Bearing
EAS00025
CIRCLIPS
Before reassembly, check all circlips carefully
and replace damaged or distorted circlips.
Always replace piston pin clips after one use.
When installing a circlip , make sure the
sharp-edged corner is positioned opposite
the thrust  that the circlip receives.
Shaft

GEN
INFO
CHECKING THE CONNECTIONS
1-4
EAS00026
CHECKING THE CONNECTIONS
Check the leads, couplers, and connectors for
stains, rust, moisture, etc.
1. Disconnect:
• lead
• coupler
• connector
2. Check:
• lead
• coupler
• connector
Moisture  Dry with an air blower.
Rust/stains  Connect and disconnect
several times.
3. Check:
• all connections
Loose connection  Connect properly.
NOTE:
If the pin on the terminal is flattened, bend
it up.
4. Connect:
• lead
• coupler
• connector
NOTE:
Make sure all connections are tight.
5. Check:
• continuity
(with the pocket tester)
NOTE:
• If there is no continuity, clean the terminals.
• When checking the wire harness, perform
steps (1) to (3).
• As a quick remedy, use a contact revitalizer
available at most part stores.
Pocket tester
90890-03112, YU-3112

GEN
INFO
SPECIAL TOOLS
1-5
EAS00027
SPECIAL TOOLS
The following special tools are necessary for complete and accurate tune-up and assembly. Use
only the appropriate special tools as this will help prevent damage caused by the use of inappro-
priate tools or improvised techniques. Special tools, part numbers or both may differ depending on
the country.
When placing an order, refer to the list provided below to avoid any mistakes.
Tool No. Tool name / Usage Illustration
90890-01312 Fuel level gauge
This gauge is used to measure the fuel level in
the float chamber.
90890-03113 Engine tachometer
This tool is needed for detecting engine rpm.
90890-04086 Universal tool of subjection of the clutch
This tool is used to immobilize the clutch
during the assembly or disassembly of the
blockade nut of the clutch.
90890-01701 Sheave holder
This tool is used for holding the secondary
sheave.
90890-01362 Flywheel puller
For removing the flywheel.
90890-01304 Piston pin puller
This tool is used to remove the piston pin.
90890-01325 Radiator cap tester
90890-01352 Adaptor
These tools are used for checking the
cooling system.

GEN
INFO
SPECIAL TOOLS
1-6
Tool No. Tool name / Usage Illustration
90890-01135 Crankcase separation tool
This tool is used to remove the crankshaft
or separate the crankcase.
90890-01274 (1) Cranckshaft intalling tool
-01275 (2) Crankshaft pin
-01278 (3) Adapter(M12)
90890-01326 T-Handle
This tool is used for holding the damper
rod holder when removing or installing
the damper rod holder.
90890-01367 Fork seal driver weight
-01381 Fork seal driver attachment
This tool is used when installing the fork seal.
90890-01403 Ring nut wrench
This tool is used to loosen and tighten
the steering ring nut.
90890-03112 Pocket tester
These instruments are invaluable for
checking the electrical system.

SPEC

2

SPEC
CHAPTER 2
SPECIFICATIONS
GENERAL SPECIFICATIONS …………………………………………………2-1
ENGINE SPECIFICATIONS……………………………………………………2-4
CHASSIS SPECIFICATIONS …………………………………………………2-6
ELECTRICAL SPECIFICATIONS ……………………………………………2-8
CONVERSION TABLE …………………………………………………………2-10
GENERAL TIGHTENING TORQUE SPECIFICATIONS ……………………2-10
ENGINE ………………………………………………………………………2-11
CHASSIS ……………………………………………………………………2-11
COOLANT FLOW CHART ……………………………………………………2-13
LUBRICATION POINTS AND LUBRICANT TYPE …………………………2-14
ENGINE ………………………………………………………………………2-14
CHASSIS ………………………………………………………………………2-15
CABLE ROUTING ………………………………………………………………2-16

SPEC
GENERAL SPECIFICATIONS
2-1
SPECIFICATIONS
GENERAL SPECIFICATIONS
Model DT125RE DT125X
Model code 1D01/1D02 2C81
Dimensions:
Overall lenght 2210mm 2139mm
Overall width 795mm 1121mm
Overall height 1200mm 1200mm
Seatheight 900mm 886mm
Wheelbase 1415mm 1396mm
Minimum ground clearance 300mm 271 mm
Minimum turning radius 2100mm 2016mm
Basic weight:
With oil and full fuel tank 126kg 134 kg
Engine:
Engine type: 2 strokes, liquid cooled
Induction system Reed valve
Cylinder arrangement Forward-inclined single cylinder
Displacement 124cm3
BorexStroke 56,0x50,7
Compression ratio 6,7:1
Maximum power 11kW /8000rpm
Maximum torque 13Nm/8000rpm
Idle speed 1250~1450r/min
Starting system Electric starter
Lubrication system Yamaha Autolube
Oil type or grade:
Engine oil 2T motor oil (JASO grade FC)
Total amount 1,3L
Transmission oil Type SE motor oil
Periodic oil change 0,75L (0,79 us. qt.)
Total amount 0,8L (0,85 us.qt.)
Radiator capacity:
Total amount (including all routes) 0,92L
Coolant reservoir capacity 0,30L
Air filter: Wet type element
Fuel
Type Regular unleaded gasoline
Fuel tank capacity: 10,7L
Reserve 1,8L
Carburetor:
Type/quantity TM28-92 / 1
Manufacturer: MIKUNI