2017 YAMAHA YS125 lock

Periodic maintenance an d a djustment
6-20
6
6. To increase the clutch lever free
play, turn the clutch lever free play
adjusting nut in direction (a). To
decrease the clutch lever free
play, turn the adjusting nut in di-
rection (b).
7. Tighten the locknut at the clutch cable, and then slide the rubber
cover to its original position.
8. Tighten the locknut at the clutch lever, and then slide the rubber
cover to its original position.
EAU37914
Checkin g the brake lever free
playThere should be no free play at the
brake lever end. If there is free play,
have a Yamaha dealer inspect the
brake system.
WARNING
EWA14212
A soft or spon gy feelin g in the brake
lever can in dicate the presence of
air in the hy draulic system. If there is
air in the hy draulic system, have a
Yamaha dealer blee d the system be-
fore operatin g the vehicle. Air in the
hy draulic system will diminish the b
rakin g performance, which may re-
sult in loss of control an d an acci-
d ent.
1. Rubber cover
2. Clutch lever free play adjusting nut
3. Locknut
3
21(b)
(a)
1. No brake lever free play
1
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Periodic maintenance an d a djustment
6-23
6 
Insufficient brake flui d may al-
low air to enter the b rake sys-
tem, re ducin g brakin g
performance.
 Clean the filler cap before re-
moving . Use only DOT 4 b rake
flui d from a seale d container.
 Use only the specified b rake flu-
i d ; otherwise, the ru bber seals
may deteriorate, causin g leak-
a g e.
 Refill with the same type of
brake flui d. A ddin g a brake flui d
other than DOT 4 may result in a
harmful chemical reaction.
 Be careful that water does not
enter the brake flui d reservoir
when refillin g. Water will si gnifi-
cantly lower the boilin g point of
the flui d an d may result in vapor
lock.
NOTICE
ECA17641
Brake flui d may damag e painted
surfaces or plastic parts. Always
clean up spille d flui d imme diately.
As the brake pads wear, it is normal for
the brake fluid level to gradually go
down. A low brake fluid level may indi-
cate worn brake pads and/or brake
system leakage; therefore, be sure to
check the brake pads for wear and the
brake system for leakage. If the brake
fluid level goes down suddenly, have a
Yamaha dealer check the cause before further riding.
EAU22724
Chan gin g the brake flui d Have a Yamaha dealer change the
brake fluid at the intervals specified in
the periodic maintenance and lubrica-
tion chart. In addition, have the oil seals
of the brake master cylinder and cali-
per as well as the brake hose replaced
at the intervals listed below or whenev-
er they are damaged or leaking.
 Oil seals: Replace every two
years.
 Brake hose: Replace every four
years.
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Periodic maintenance an d a djustment
6-24
6
EAU22762
Drive chain slackThe drive chain slack should be
checked before each ride and adjusted
if necessary.
EAU22799
To check the drive chain slack
1. Place the motorcycle on the cen- terstand.
2. Shift the transmission into the neutral position.
3. Measure the drive chain slack as shown. 4. If the drive chain slack is incorrect,
adjust it as follows. NOTICE: Im-
proper drive chain slack will
overloa d the en gine as well as
other vital parts of the motorcy-
cle an d can lead to chain slip-
pa ge or b reakag e. To prevent
this from occurrin g, keep the
d rive chain slack within the
specifie d limits.
[ECA10572]
EAU78831
To adjust the drive chain slack
Consult a Yamaha dealer before ad-
justing the drive chain slack. 1. Take the motorcycle off the cen- terstand, and then put the side-
stand down.
2. Loosen the brake pedal free play adjusting nut, brake torque rod
nut, and axle nut.
3. Loosen the drive chain puller lock-nut at each end of the swingarm.
1. Drive chain slackDrive chain slack:40.0–50.0 mm (1.57–1.97 in)
1
1. Brake pedal free play adjusting nut
2. Brake torque rod nut
1. Axle nut
2. Drive chain slack adjusting nut
3. Drive chain puller locknut
4. Drive chain puller
1
2
4 31
2
(a)(b)
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Periodic maintenance an d a djustment
6-25
6 4. Place the motorcycle on the cen-
terstand.
5. To tighten the drive chain, turn the drive chain slack adjusting nut at
each end of the swingarm in direc-
tion (a). To loosen the drive chain,
turn the adjusting nut at each end
of the swingarm in direction (b),
and then push the rear wheel for-
ward.
TIPUsing the alignment marks on each
drive chain puller, make sure that both
drive chain pullers are in the same po-
sition for proper wheel alignment.
6. Take the motorcycle off the cen-terstand, and then put the side-
stand down.
7. Tighten both locknuts, and then tighten the axle nut and brake
torque rod nut to their specified
torques.
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.9. Make sure that the drive chain
pullers are in the same position,
the drive chain slack is correct,
and the drive chain moves
smoothly.
EAU23018
Cleanin g an d lu bricatin g the
d rive chainThe drive chain must be cleaned and
lubricated at the intervals specified in
the periodic maintenance and lubrica-
tion chart, otherwise it will quickly wear
out, especially when riding in dusty or
wet areas. Service the drive chain as
follows.NOTICE
ECA10584
The drive chain must be lu bricated
after washin g the motorcycle, ri din g
in the rain or ri din g in wet areas.1. Remove all dirt and mud from the
drive chain with a brush or cloth.TIPFor a thorough cleaning, have a
Yamaha dealer remove the drive chain and soak it in solvent.2. Spray Yamaha chain lubricant or other suitable chain lubricant on
the entire chain, making sure that
all side plates and rollers have
been sufficiently oiled.
1. Washer
2. Alignment marks
1
2
Tightenin g torques:
Locknut: 7 N·m (0.7 kgf·m, 5.1 lb·ft)
Axle nut:
90 N·m (9.0 kgf·m, 65 lb·ft)
Brake torque rod nut: 18 N·m (1.8 kgf·m, 13 lb·ft)
UBT4E0E0.book Page 25 Thursday, November 17, 2016 10:55 AM

Periodic maintenance an d a djustment
6-35
6
EAU78920
Replacin g the brake/tail li ght
b ul b1. Remove the seat. (See page 3-11.)
2. Remove the brake/tail light bulb
socket (together with the bulb) by
turning it counterclockwise.
3. Remove the burnt-out bulb by pushing it in and turning it coun-
terclockwise. 4. Insert a new bulb into the socket,
push it in, and then turn it clock-
wise until it stops.
5. Install the socket (together with the bulb) by turning it clockwise.
6. Install the seat.
EAU24205
Replacin g a turn si gnal li ght
b ul b1. Remove the turn signal light lens
by removing the screw.
2. Remove the burnt-out bulb by pushing it in and turning it coun-
terclockwise.
1. Brake/tail light bulb socket
1
1. Brake/tail light bulb1
1. Turn signal light lens
2. Screw
1
2
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Periodic maintenance an d a djustment
6-36
6
3. Insert a new bulb into the socket,
push it in, and then turn it clock-
wise until it stops.
4. Install the lens by installing the screw. NOTICE: Do not over-
ti g hten the screw, otherwise the
lens may break.
[ECA11192] EAU78970
Replacin
g the license plate
lig ht bul b1. Remove the license plate light unit
by removing the nuts.
2. Remove the license plate light bulb socket (together with the
bulb) by pulling it out.
3. Remove the burnt-out bulb by pulling it out.
4. Insert a new bulb into the socket.
5. Install the socket (together with the bulb) by pushing it in.
6. Install the license plate light unit by installing the nuts.
EAU24361
Front wheel
EAUW3361
To remove the front wheel
WARNING
EWA10822
To avoi d injury, securely support the
vehicle so there is no dan ger of it
fallin g over.1. Take the vehicle off the center-
stand so that the front wheel is on
the ground, and then put the side-
stand down.
2. Loosen the front wheel axle nut.
1. Turn signal light bulb
1
1. License plate light unit
2. License plate light bulb
3. License plate light bulb socket
4. Nut
1
32
4
4
1. Axle nut
1
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Periodic maintenance an d a djustment
6-38
6
4. Remove the brake pedal free play
adjusting nut, and then discon-
nect the brake rod from the brake
camshaft lever.
5. Loosen the drive chain puller lock-nut and the drive chain slack ad-
justing nut on both ends of the
swingarm.
6. Place the motorcycle on the cen- terstand.
7. Remove the axle nut and the washer, then pull the wheel axle
together with the washer out from
the right side, and then remove
the collars.
TIPA rubber mallet may be useful to tap
the wheel axle out.8. Push the wheel forward, and thenremove the drive chain from the
rear sprocket.
1. Axle nut
1
1. Brake pedal free play adjusting nut
2. Brake camshaft lever
3. Drive chain puller locknut
4. Drive chain slack adjusting nut
5. Brake shoe plate
6. Brake rod
7. Brake torque rod
8. Brake torque rod bolt
9. Brake torque rod nut
234
5
67
1
98
1. Washer
2. Collar
3. Wheel axle
2
1
2
31
UBT4E0E0.book Page 38 Thursday, November 17, 2016 10:55 AM

10-1
10
IndexAAir filter element and check hose,
cleaning .............................................. 6-14
Auxiliary light bulb, replacing ................ 6-34BBattery .................................................. 6-30
Brake and clutch levers, checking and lubricating ........................................... 6-27
Brake and shift pedals, checking and
lubricating ........................................... 6-26
Brake fluid, changing ............................ 6-23
Brake fluid level, checking .................... 6-22
Brake lever .............................................. 3-7
Brake lever free play, checking............. 6-20
Brake light switches.............................. 6-21
Brake pads and shoes, checking ......... 6-22
Brake pedal............................................. 3-7
Brake pedal free play, adjusting ........... 6-21
Brake/tail light bulb, replacing .............. 6-35CCables, checking and lubricating ......... 6-26
Care ........................................................ 7-1
Catalytic converters .............................. 3-10
Centerstand and sidestand, checking and lubricating .................................... 6-28
Clutch lever ............................................. 3-6
Clutch lever free play, adjusting ........... 6-19
Cowling and panels, removing and installing................................................ 6-8DData recording, vehicle ........................... 9-2
Diagnostic connector.............................. 9-2
Dimmer switch ........................................ 3-5
Drive chain, cleaning and lubricating .... 6-25 Drive chain slack .................................. 6-24
EEco indicator light................................... 3-2
Engine break-in ...................................... 5-3
Engine idling speed .............................. 6-16
Engine oil and oil filter element ............ 6-11
Engine serial number .............................. 9-1
Engine trouble warning light ................... 3-2FFront fork, checking ............................. 6-29
Fuel ......................................................... 3-8
Fuel consumption, tips for reducing ...... 5-3
Fuel tank cap .......................................... 3-8
Fuse, replacing ..................................... 6-31HHandlebar switches ................................ 3-5
Headlight bulb, replacing ..................... 6-33
High beam indicator light ....................... 3-2
Horn switch ............................................ 3-5IIdentification numbers ............................ 9-1
Ignition circuit cut-off system ............... 3-13
Indicator lights and warning light ........... 3-2LLicense plate light bulb, replacing........ 6-36MMain 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 ........................ 3-3
NNeutral indicator light ..............................3-2PParking ....................................................5-4
Part locations ..........................................2-1
Pass switch .............................................3-5SSafety information ...................................1-1
Seat .......................................................3-11
Shifting ....................................................5-2
Shift pedal ...............................................3-6
Shock absorber assemblies, adjusting .............................................3-11
Sidestand ..............................................3-12
Spark plug, checking ............................6-10
Specifications .........................................8-1
Starting the engine ..................................5-1
Start switch .............................................3-6
Steering, checking ................................6-29
Storage ...................................................7-3
Swingarm pivots, lubricating ................6-28TThrottle grip and cable, checking and lubricating ...........................................6-26
Throttle grip free play, checking ...........6-16
Tires ......................................................6-17
Tool kit ....................................................6-2
Troubleshooting ....................................6-39
Troubleshooting chart ...........................6-41
Turn signal indicator light........................3-2
Turn signal light bulb, replacing ............6-35
Turn signal switch ...................................3-5VValve clearance .....................................6-17
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