2015 YAMAHA MT-125 check engine

PERIODIC MAINTENANCE AND ADJUSTMENT
6-41
6
EAUM2443
Troubleshooting chartsStarting problems or poor engine performance
Check the fuel level in
the fuel tank.1. Fuel
There is enough fuel.
There is no fuel.
Check the compression.
Supply fuel.
Operate the electric starter.2. Compression
There is compression.
There is no compression.
Check the ignition.
Have a Yamaha dealer
check the vehicle.
Remove the spark plug
and check the electrodes.3. Ignition
Wet
Dry
Wipe off with a dry cloth and correct the
spark plug gap, or replace the spark plug.
Have a Yamaha dealer check the vehicle.The engine does not start.
Check the battery.
Operate the electric starter.
Operate the electric starter.4. Battery
The engine turns over
quickly.
The engine turns over
slowly.The battery is good.
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.
The engine does not start.
Check the compression.
U5D7E4E0.book Page 41 Thursday, July 10, 2014 3:01 PM

PERIODIC MAINTENANCE AND ADJUSTMENT
6-42
6Engine 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 counterclockwise to the detent to allow any residual pressure to escape. When the hiss-
ing sound has stopped, press down on the cap while turning it counterclockwise, and then remove the cap.TIPIf coolant is not available, tap water can be temporarily used instead, provided that it is changed to the recommended cool-
ant as soon as possible.
Wait until the
engine has cooled.
Check the coolant level in the
reservoir and radiator.
The coolant level
is OK.The coolant level is low.
Check the cooling system
for leakage.
Have a Yamaha dealer checkand repair the cooling system.Add coolant. (See TIP.)
Start the engine. If the engine overheats again,
have a
Yamaha dealer check
and repair the cooling system.
There is
leakage.
There is
no leakage.
U5D7E4E0.book Page 42 Thursday, July 10, 2014 3:01 PM

MOTORCYCLE CARE AND STORAGE
7-4
72. Fill up the fuel tank and add fuel
stabilizer (if available) to prevent
the fuel tank from rusting and the
fuel from deteriorating.
3. Perform the following steps to
protect the cylinder, piston rings,
etc. from corrosion.
a. Remove the spark plug cap
and spark plug.
b. Pour a teaspoonful of engine
oil into the spark plug bore.
c. Install the spark plug cap onto
the spark plug, and then place
the spark plug on the cylinder
head so that the electrodes are
grounded. (This will limit spark-
ing during the next step.)
d. Turn the engine over several
times with the starter. (This will
coat the cylinder wall with oil.)
e. Remove the spark plug cap
from the spark plug, and then
install the spark plug and the
spark plug cap. WARNING! To
prevent damage or injury
from sparking, make sure to
ground the spark plug elec-
trodes while turning the en-
gine over.
[EWA10952]
4. Lubricate all control cables and
the pivoting points of all levers and
pedals as well as of the side-
stand/centerstand.
5. Check and, if necessary, correct
the tire air pressure, and then lift
the motorcycle so that both of its
wheels are off the ground. Alterna-
tively, turn the wheels a little every
month in order to prevent the tires
from becoming degraded in one
spot.
6. Cover the muffler outlet with a
plastic bag to prevent moisture
from entering it.
7. Remove the battery and fully
charge it. Store it in a cool, dry
place and charge it once a month.
Do not store the battery in an ex-
cessively cold or warm place [less
than 0 °C (30 °F) or more than 30
°C (90 °F)]. For more information
on storing the battery, see page
6-30.TIPMake any necessary repairs before
storing the motorcycle.
U5D7E4E0.book Page 4 Thursday, July 10, 2014 3:01 PM

10-1
10
INDEX
AABS (for ABS models) .......................... 3-14
ABS warning light (for ABS models) ....... 3-3
Air filter element and check hose,
replacing and cleaning ....................... 6-14
Auxiliary light ........................................ 6-34BBattery .................................................. 6-30
Brake and clutch levers, checking and
lubricating........................................... 6-26
Brake fluid, changing............................ 6-23
Brake fluid level, checking.................... 6-22
Brake lever............................................ 3-13
Brake light switches ............................. 6-21
Brake pedal .......................................... 3-14
Brake pedal, checking and
lubricating........................................... 6-27
Brake pedal free play, adjusting ........... 6-20CCables, checking and lubricating ......... 6-26
Care ........................................................ 7-1
Catalytic converter ............................... 3-17
Clutch lever........................................... 3-13
Clutch lever free play, adjusting ........... 6-19
Coolant ................................................. 6-13
Cowlings, removing and installing.......... 6-8DDimmer switch...................................... 3-12
Drive chain, cleaning and lubricating ... 6-25
Drive chain slack .................................. 6-24EEngine break-in ...................................... 5-3
Engine idling speed, checking.............. 6-15
Engine oil and oil filter element............. 6-10Engine stop switch............................... 3-12
Engine trouble warning light .................. 3-3
FFront and rear brake pads, checking ... 6-21
Front brake lever free play, checking ... 6-20
Front fork, checking ............................. 6-28
Fuel ...................................................... 3-16
Fuel consumption, tips for reducing ...... 5-3
Fuel level warning light........................... 3-2
Fuel tank cap........................................ 3-15
Fuses, replacing ................................... 6-31HHandlebar switches ............................. 3-11
Headlight bulb, replacing ..................... 6-33
High beam indicator light ....................... 3-2
Horn switch .......................................... 3-12IIdentification numbers ........................... 9-1
Ignition circuit cut-off system .............. 3-19
Indicator lights and warning lights ......... 3-2
Info switch ............................................ 3-12LLicense plate light bulb, replacing ....... 6-35MMain 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 ........................ 3-4NNeutral indicator light ............................. 3-2
PParking.................................................... 5-4
Part locations.......................................... 2-1
Pass switch........................................... 3-12RRider seat.............................................. 3-18SSafety information................................... 1-1
Shifting.................................................... 5-2
Shift pedal............................................. 3-13
Sidestand.............................................. 3-18
Sidestand, checking and lubricating .... 6-27
Spark plug, checking .............................. 6-9
Specifications ......................................... 8-1
Starting the engine ................................. 5-1
Start switch ........................................... 3-12
Steering, checking ................................ 6-29
Storage ................................................... 7-3
Supporting the motorcycle ................... 6-36
Swingarm pivots, lubricating ................ 6-28TTail/brake light ...................................... 6-34
Throttle grip and cable, checking and
lubricating ........................................... 6-26
Throttle grip free play, adjusting ........... 6-15
Tires ...................................................... 6-16
Tool kit .................................................... 6-2
Troubleshooting .................................... 6-40
Troubleshooting charts ......................... 6-41
Turn signal indicator light ....................... 3-2
Turn signal light bulb, replacing............ 6-35
Turn signal switch ................................. 3-12VValve clearance..................................... 6-16
U5D7E4E0.book Page 1 Thursday, July 10, 2014 3:01 PM