maintenance YAMAHA MT-125 2017 Service Manual

Periodic maintenance and adjustment
6-37
6
EAU67131
Supporting the motorcycle
Since this model is not equipped with a
centerstand, use maintenance stands
when removing the front or rear wheel
or when performing other maintenance
that requires the motorcycle to stand
up right.
Check that the motorcycle is in a stable
and level position before starting any
maintenance.
EAU25872
Troubleshooting
Although Yamaha motorcycles receive
a thorough inspection before shipment
from the factory, trouble may occur
during operation. Any problem in the
fuel, compression, or ignition systems,
for example, can cause poor starting
and loss of power.
The following troubleshooting charts
represent quick and easy procedures
for checking these vital systems your-
self. However, should your motorcycle
require any repair, take it to a Yamaha
dealer, whose skilled technicians have
the necessary tools, experience, and
know-how to service the motorcycle
properly.
Use only genuine Yamaha replace-
ment parts. Imitation parts may look
like Yamaha parts, but they are often
inferior, have a shorter service life and
can lead to expensive repair bills.
WARNING
EWA15142
When checking the fuel system, do
not smoke, and make sure there are
no open flames or sparks in the ar-
ea, including pilot lights from water
heaters or furnaces. Gasoline or
gasoline vapors can ignite or ex-
plode, causing severe injury or prop-
erty damage.
1. Maintenance stand (example)
1
UBR3E1E0.book Page 37 Wednesday, August 10, 2016 9:45 AM

Periodic maintenance and adjustment
6-38
6
EAU68070
Troubleshooting charts
Starting problems or poor engine performance
1. FuelThere is enough fuel.
There is no fuel.Supply fuel.
The engine turns over
quickly.
Operate the electric
starter.
Check the
compression.
The engine turns over
slowly.
Wipe off with a dry
cloth and correct the
spark plug gap, or
replace the spark
plug.
Check the electrolyte
and battery lead
connections, and
charge the battery if
necessary.
The engine does not
start.
Have a Yamaha
dealer check the
vehicle.
4. BatteryThe battery is good.
3. IgnitionWet
Dry
The engine does not
start.
Check the
compression.
Have a Yamaha
dealer check the
vehicle.The engine does not
start.
Check the battery.
Remove the spark
plug and check
the electrodes.
Check the fuel level
in the fuel tank.
Operate the electric
starter.
Operate the electric
starter.
There is compression.
There is no
compression.Have a Yamaha dealer check the vehicle.
Check the ignition.2. Compression
UBR3E1E0.book Page 38 Wednesday, August 10, 2016 9:45 AM

Periodic maintenance and adjustment
6-39
6 Engine overheating
WARNING
EWA10401
Do not remove the radiator cap when the engine and radiator are hot.
Scalding hot fluid and steam may be blown out under pressure, which
could cause serious injury. Be sure to wait until the engine has cooled.
After removing the radiator cap retaining bolt, place a thick rag, like a
towel, over the radiator cap, and then slowly rotate the cap counter-
clockwise to the detent to allow any residual pressure to escape. When
the hissing sound has stopped, press down on the cap while turning it
counterclockwise, and then remove the cap.
TIP
If coolant is not available, tap water can be temporarily used instead, provided
that it is changed to the recommended coolant as soon as possible.
Wait until the engine
has cooled.
Check the coolant
level in the reservoir
and radiator.Add coolant.
(See TIP.)
The coolant level is
OK.
There is no leakage.
There is leakage.
The coolant level is
low.
Check the cooling
system for leakage.
Have a Yamaha
dealer check and
repair the cooling
system.
Start the engine. If the engine overheats again,
have a Yamaha dealer check and repair the cooling
system.
UBR3E1E0.book Page 39 Wednesday, August 10, 2016 9:45 AM

Consumer information
9-2
9
EAUM3880
Diagnostic connectors
The ABS and Fuel Injection diagnostic
connectors are located as shown.
EAU85300
Vehicle data recording
This model’s ECU stores certain vehi-
cle data to assist in the diagnosis of
malfunctions and for research, statisti-
cal analysis and development purpos-
es.
Although the sensors and recorded
data will vary by model, the main data
points are: Vehicle status and engine perfor-
mance data
 Fuel-injection and emission-relat-
ed data
This data will be uploaded only when a
special Yamaha diagnostic tool is at-
tached to the vehicle, such as when
maintenance checks or service proce-
dures are performed.
Vehicle data uploaded will be handled
appropriately according to the follow-
ing Privacy Policy.
Privacy Policy
Yamaha will not disclose this data to a third party except in the following cas-
es. In addition, Yamaha may provide
vehicle data to a contractor in order to
outsource services related to the han-
dling of vehicle data. Even in this case,
Yamaha will require the contractor to properly handle the vehicle data we
provided and Yamaha will appropriate-
ly manage the data.  With the consent of the vehicle
owner
 Where obligated by law
 For use by Yamaha in litigation
 When the data is not related to an
individual vehicle nor owner
1. FI diagnostic connector
2. ABS diagnostic connector
3. Fuse box
ZAUM1451
2
3
https://www.yamaha-motor.eu/eu/
privacy/privacy-policy.aspx
UBR3E2E0.book Page 2 Friday, May 11, 2018 11:09 AM

10-1
10
Index
A
ABS ....................................................... 3-15
ABS warning light ................................... 3-3
Air filter element and check hose,
replacing and cleaning ....................... 6-14
Auxiliary lights ....................................... 6-35
B
Battery .................................................. 6-31
Brake and clutch levers, checking and
lubricating ........................................... 6-27
Brake fluid, changing ............................ 6-24
Brake fluid level, checking .................... 6-23
Brake lever ............................................ 3-14
Brake light switches.............................. 6-21
Brake pedal........................................... 3-15
Brake pedal, checking and
lubricating ........................................... 6-28
Brake pedal free play, adjusting ........... 6-21
C
Cables, checking and lubricating ......... 6-26
Care ........................................................ 7-1
Catalytic converter ................................ 3-18
Clutch lever ........................................... 3-13
Clutch lever free play, adjusting ........... 6-19
Coolant ................................................. 6-12
Cowlings, removing and installing .......... 6-7
D
Data recording, vehicle ........................... 9-2
Diagnostic connectors ............................ 9-2
Dimmer switch ...................................... 3-12
Drive chain, cleaning and lubricating .... 6-26
Drive chain slack................................... 6-24
E
Engine break-in....................................... 5-4
Engine idling speed, checking .............. 6-14
Engine oil and oil filter element ............... 6-9
Engine stop switch ............................... 3-12
Engine trouble warning light ................... 3-3
F
Front and rear brake pads, checking.... 6-22
Front brake lever free play, checking ... 6-20
Front fork, checking .............................. 6-29
Fuel ....................................................... 3-17
Fuel consumption, tips for reducing ....... 5-4
Fuel level warning light ........................... 3-2
Fuel tank cap ........................................ 3-16
Fuses, replacing.................................... 6-32
H
Handlebar switches .............................. 3-12
Headlight bulb, replacing ...................... 6-33High beam indicator light ....................... 3-2
Horn switch .......................................... 3-12
I
Identification numbers ............................ 9-1
Ignition circuit cut-off system............... 3-20
Indicator lights and warning lights ......... 3-2
Info switch ............................................ 3-12
L
License plate light bulb, replacing........ 6-36
M
Main switch/steering lock....................... 3-1
Maintenance and lubrication, periodic ... 6-4
Maintenance, emission control
system.................................................. 6-3
Matte color, caution ............................... 7-1
Model label ............................................. 9-1
Multi-function meter unit ........................ 3-4
N
Neutral indicator light ............................. 3-2
P
Parking ................................................... 5-5
Part locations ......................................... 2-1
Pass switch .......................................... 3-12
R
Rider seat ............................................. 3-19
S
Safety information .................................. 1-1
Shifting ................................................... 5-3
Shift pedal ............................................ 3-14
Sidestand ............................................. 3-20
Sidestand, checking and lubricating .... 6-28
Spark plug, checking ............................. 6-8
Specifications ......................................... 8-1
Starting the engine ................................. 5-2
Start switch .......................................... 3-12
Steering, checking................................ 6-30
Storage ................................................... 7-4
Supporting the motorcycle................... 6-37
Swingarm pivots, lubricating ................ 6-29
T
Tail/brake light ...................................... 6-35
Throttle grip and cable, checking and
lubricating .......................................... 6-27
Throttle grip free play, adjusting........... 6-15
Tires ...................................................... 6-16
Tool kit.................................................... 6-2
Troubleshooting ................................... 6-37
Troubleshooting charts ........................ 6-38
Turn signal indicator light ....................... 3-2
Turn signal light bulb, replacing ........... 6-36
UBR3E1E0.book Page 1 Wednesday, August 10, 2016 9:45 AM