2017 YAMAHA YS125 ignition

Table of contentsSafety information ............................ 1-1
Description ....................................... 2-1
Left view ......................................... 2-1
Right view ....................................... 2-2
Controls and instruments ............... 2-3
Instrument an d control functions ... 3-1
Main switch/steering lock............... 3-1
Indicator lights and warning light ............................................. 3-2
Multi-function meter unit ................ 3-3
Handlebar switches ........................ 3-5
Clutch lever .................................... 3-6
Shift pedal ...................................... 3-6
Brake lever...................................... 3-7
Brake pedal .................................... 3-7
Fuel tank cap .................................. 3-8
Fuel ................................................. 3-8
Catalytic converters ..................... 3-10
Seat .............................................. 3-11
Adjusting the shock absorber assemblies ................................ 3-11
Sidestand ..................................... 3-12
Ignition circuit cut-off system ....... 3-13 For your safety – pre-operation
checks
............................................... 4-1
Operation an d important ri din g
points ................................................. 5-1
Starting the engine .......................... 5-1
Shifting ............................................ 5-2
Tips for reducing fuel consumption ................................ 5-3
Engine break-in ............................... 5-3
Parking ............................................ 5-4
Perio dic maintenance an d
a d justment ........................................ 6-1
Owner’s tool kit ............................... 6-2
Periodic maintenance chart for the emission control system .............. 6-3
General maintenance and lubrication chart ........................... 6-4
Removing and installing the
cowling and panels ...................... 6-8
Checking the spark plug ............... 6-10
Engine oil and oil filter element ..... 6-11
Cleaning the air filter element and cleaning the check hose ............ 6-14
Adjusting the engine idling
speed ......................................... 6-16
Checking the throttle grip free play ............................................ 6-16
Valve clearance ............................. 6-17
Tires .............................................. 6-17 Cast wheels .................................. 6-19
Adjusting the clutch lever free
play ............................................ 6-19
Checking the brake lever free play ............................................ 6-20
Adjusting the brake pedal free play ............................................ 6-21
Brake light switches ..................... 6-21
Checking the front brake pads
and rear brake shoes ............... 6-22
Checking the brake fluid level ...... 6-22
Changing the brake fluid ............. 6-23
Drive chain slack........................... 6-24
Cleaning and lubricating the
drive chain ................................. 6-25
Checking and lubricating the cables ........................................ 6-26
Checking and lubricating the throttle grip and cable ............... 6-26
Checking and lubricating the
brake and shift pedals............... 6-26
Checking and lubricating the brake and clutch levers ............. 6-27
Checking and lubricating the centerstand and sidestand........ 6-28
Lubricating the swingarm
pivots......................................... 6-28
Checking the front fork ................. 6-29
Checking the steering................... 6-29
Checking the wheel bearings ....... 6-30
Battery .......................................... 6-30UBT4E0E0.book Page 1 Thursday, November 17, 2016 10:55 AM

Instrument and control functions
3-1
3
EAU10462
Main switch/steerin g lockThe main switch/steering lock controls
the ignition and lighting systems, and is
used to lock the steering. The various
positions are described below.
EAU78890
(on)
All electrical circuits are supplied with
power and the vehicle lights are turned
on. The engine can be started. The key
cannot be removed.
TIPTo prevent draining the battery, do not
leave the key in the on position for an
extended time without the engine run-
ning.
EAU54301
(off)
All electrical systems are off. The key
can be removed.
WARNING
EWA16371
Never turn the key to “ ” or “LOCK”
while the vehicle is movin g. Other-
wise the electrical systems will be
switched off, which may result in
loss of control or an acci dent.
EAU73820
LOCK
The steering is locked, and all electrical
systems are off. The key can be re-
moved. To lock the steering
1. Turn the handlebars all the way to
the left or right.
2. With the key in the “ ” position, push the key in and turn it to
“LOCK”.
3. Remove the key.TIPIf the steering will not lock, try turning
the handlebars back to the right or left
slightly.
LOCK
1. Push.
2. Turn.12
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Instrument and control functions
3-8
3
EAU13003
Fuel tank capTo remove the fuel tank cap
Insert the key into the lock and turn it
1/4 turn clockwise. The lock will be re-
leased and the fuel tank cap can be re-
moved.
To install the fuel tank cap
1. Push the fuel tank cap into posi- tion with the key inserted in the
lock.
2. Turn the key counterclockwise to the original position, and then re-
move it.
TIPThe fuel tank cap cannot be installed
unless the key is in the lock. In addi-
tion, the key cannot be removed if the
cap is not properly installed and
locked.
WARNING
EWA11142
Make sure that the fuel tank cap is
properly installe d before ri din g.
Leakin g fuel is a fire hazar d.
EAU13213
FuelMake sure there is sufficient gasoline in
the tank.
WARNING
EWA10882
Gasoline an d gasoline vapors are
extremely flammab le. To avoid fires
an d explosions an d to re duce the
risk of injury when refuelin g, follow
these instructions.1. Before refueling, turn off the en- gine and be sure that no one is sit-
ting on the vehicle. Never refuel
while smoking, or while in the vi-
cinity of sparks, open flames, or
other sources of ignition such as
the pilot lights of water heaters
and clothes dryers.
2. Do not overfill the fuel tank. Stop filling when the fuel reaches the
bottom of the filler tube. Because
fuel expands when it heats up,
heat from the engine or the sun
can cause fuel to spill out of the
fuel tank.
1. Unlock.
1
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Instrument and control functions
3-12
3

Align the appropriate notch in the
adjusting ring with the position in-
dicator on the shock absorber.
 Use the screwdriver included in
the owner’s tool kit to make this
adjustment.
EAU15306
Sidestan dThe sidestand is located on the left
side of the frame. Raise the sidestand
or lower it with your foot while holding
the vehicle upright.TIPThe built-in sidestand switch is part of
the ignition circuit cut-off system,
which cuts the ignition in certain situa-
tions. (See the following section for an
explanation of the ignition circuit cut-
off system.)
WARNING
EWA10242
The vehicle must not b e ridden with
the si destan d d own, or if the si de-
stan d cannot b e properly move d up
(or does not stay up), otherwise the
si destan d coul d contact the groun d
an d d istract the operator, resultin g
in a possib le loss of control.
Yamaha’s ig nition circuit cut-off
system has been desi gne d to assist
the operator in fulfillin g the respon-
si bility of raisin g the si destan d b e-
fore startin g off. Therefore, check this system re
gularly an d have a
Yamaha dealer repair it if it does not
function properly.
1. Spring preload adjusting ring
2. Position indicator
3. ScrewdriverSprin g preloa d settin g:
Minimum (soft):
1
Standard: 2
Maximum (hard): 5
2
13(a)
(b)
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Instrument and control functions
3-13
3
EAU78340
Ig nition circuit cut-off systemThe ignition circuit cut-off system
(comprising the sidestand switch,
clutch switch and neutral switch) has
the following functions.
 It prevents starting when the
transmission is in gear and the
sidestand is up, but the clutch le-
ver is not pulled.
 It prevents starting when the
transmission is in gear and the
clutch lever is pulled, but the side-
stand is still down.
 It cuts the running engine when
the transmission is in gear and the
sidestand is moved down.
Periodically check the operation of the
ignition circuit cut-off system accord-
ing to the following procedure.UBT4E0E0.book Page 13 Thursday, November 17, 2016 10:55 AM

For your safety – pre-operation checks
4-2
4
Throttle grip • Make sure that operation is smooth.
• Check throttle grip free play.
• If necessary, have Yamaha dealer adjust throttle grip free play and lubricate ca-
ble and grip housing. 6-16, 6-26
Control ca bles • Make sure that operation is smooth.
• Lubricate if necessary.
6-26
Drive chain • Check chain slack.
• Adjust if necessary.
• Check chain condition.
• Lubricate if necessary. 6-24, 6-25
Wheels an d tires • Check for damage.
• Check tire condition and tread depth.
• Check air pressure.
• Correct if necessary. 6-17, 6-19
Brake an d shift pe dals • Make sure that operation is smooth.
• Lubricate pedal pivoting points if necessary.
6-26
Brake an d clutch levers • Make sure that operation is smooth.
• Lubricate lever pivoting points if necessary. 6-27
Centerstan d, si destan d • Make sure that operation is smooth.
• Lubricate pivots if necessary. 6-28
Chassis fasteners • Make sure that all nuts, bolts and screws are properly tightened.
• Tighten if necessary.
—
Instruments, li ghts, si gnals
an d switches • Check operation.
• Correct if necessary.
—
Si destan d switch • Check operation of ignition circuit cut-off system.
• If system is not working correctly, have Yamaha dealer check vehicle. 3-12
ITEM CHECKS PAGE
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Operation and important rid ing points
5-1
5
EAU15952
Read the Owner’s Manual carefully to
become familiar with all controls. If
there is a control or function you do not
understand, ask your Yamaha dealer.
WARNING
EWA10272
Failure to familiarize yourself with
the controls can lead to loss of con-
trol, which coul d cause an acci dent
or injury.
EAUM3150
TIPThis model is equipped with a lean an-
gle sensor to stop the engine in case of
a turnover. To start the engine after a
turnover, be sure to turn the main
switch to “ ” and then to “ ”. Failing
to do so will prevent the engine from
starting even though the engine will
crank when pushing the start switch.
EAU78350
Startin g the en gineIn order for the ignition circuit cut-off
system to enable starting, one of the
following conditions must be met:
 The transmission is in the neutral
position.
 The transmission is in gear with
the clutch lever pulled and the
sidestand up.
See page 3-13 for more informa-
tion.
1. Turn the key to “ ”. The engine trouble warning light
should come on for a few sec-
onds, then go off.NOTICE
ECA23970
If the warnin g li ght does not come
on initially when the key is turne d
to “ ”, or if the warnin g li ght re-
mains on, see pag e 3-2 for the warn-
in g lig ht circuit check.2. Shift the transmission into the
neutral position. The neutral indi-
cator light should come on. If not,
ask a Yamaha dealer to check the
electrical circuit.
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Periodic maintenance an d a djustment
6-39
6
TIPThe drive chain does not need to be
disassembled in order to remove and
install the wheel.9. Remove the wheel.
To install the rear wheel 1. Install the drive chain onto the rear sprocket.
2. Install the wheel by installing the collars on both sides and installing
the washer and the wheel axle
from the right side.
3. Install the washer and the axle nut.
4. Connect the brake rod to the brake camshaft lever, and then in-
stall the brake pedal free play ad-
justing nut onto the brake rod.
5. Connect the brake torque rod to the brake shoe plate by installing
the bolt and the nut.
6. Adjust the drive chain slack. (See page 6-24.)
7. Take the motorcycle off the cen- terstand so that the rear wheel is
on the ground, and then put the
sidestand down. 8. Adjust the brake pedal free play.
(See page 6-21.)
WARNING
EWA10661
After a djustin g the brake pe dal free
play, check the operation of the
b rake li ght.
EAU25853
Trou bleshootin gAlthough 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 chart
represents a quick and easy procedure
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 checkin g the fuel system, do
not smoke, an d make sure there are
no open flames or sparks in the ar-
ea, inclu din g pilot li ghts from water
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