2021 YAMAHA MT-125 Owners Manual

Periodic maintenance an d a djustment
6-21
6
EAUM1355
A djustin g the brake pe dal free
playMeasure the brake pedal free play as
shown.
Periodically check the brake pedal free
play and, if necessary, have a Yamaha
dealer adjust it.
WARNING
EWAM1031
An incorrect brake pe dal free play
in dicates a hazar dous con dition in
the brake system. Do not operate the motorcycle until the
brake sys-
tem has b een checked or repaired
b y a Yamaha dealer.
EAU36505
Brake li ght switchesThe brake light should come on just
before braking takes effect. The brake
light is activated by switches connect-
ed to the brake lever and brake pedal.
Since the brake light switches are
components of the anti-lock brake sys-
tem, they should only be serviced by a
Yamaha dealer.
1. Brake pedal free playBrake pe dal free play:
7.0–13.0 mm (0.28–0.51 in)
1
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Periodic maintenance an d a djustment
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EAU22393
Checkin g the front an d rear
b rake pa dsThe front and rear brake pads must be
checked for wear at the intervals spec-
ified in the periodic maintenance and
lubrication chart.
EAU22421
Front brake pa ds
Each front brake pad is provided with a
wear indicator groove, which allows
you to check the brake pad wear with-
out having to disassemble the brake.
To check the brake pad wear, check
the wear indicator groove. If a brake
pad has worn to the point that the wear indicator groove has almost disap-
peared, have a Yamaha dealer replace
the brake pads as a set.
EAU36721
Rear
brake pad s
Each rear brake pad is provided with
wear indicator grooves, which allow
you to check the brake pad wear with-
out having to disassemble the brake.
To check the brake pad wear, check
the wear indicator grooves. If a brake
pad has worn to the point that the wear
indicator grooves have almost disap-
peared, have a Yamaha dealer replace
the brake pads as a set.
EAU40262
Checkin g the brake flui d levelBefore riding, check that the brake fluid
is above the minimum level mark.
Check the brake fluid level with the top
of the reservoir level. Replenish the
brake fluid if necessary.
Front brake
1. Wear indicator grooveZAUM1466
1
1. Wear indicator grooveZAUM1601
1
1
1. Minimum level mark
1
ZAUM1057
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Periodic maintenance an d a djustment
6-23
6
Rear
brake
WARNING
EWA16011
Improper maintenance can result in
loss of b raking a bility. O bserve
these precautions:  Insufficient brake flui d may al-
low air to enter the brake sys-
tem, re ducin g brakin g
performance.
 Clean the filler cap before re-
movin g. Use only DOT 4 brake
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 dding a brake fluid
other than DOT 4 may result in a
harmful chemical reaction.
 Be careful that water or d ust
d oes not enter the brake flui d
reservoir when refillin g. Water
will si gnificantly lower the boil-
in g point of the flui d an d may re-
sult in vapor lock, an d d ir
t may
clo g the ABS hy draulic unit
valves.
NOTICE
ECA17641
Brake flui d may d amage painte d
surfaces or plastic parts. Always
clean up spilled fluid 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.
1. Minimum level markSpecifie
d b rake flui d:
DOT 4
1
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Periodic maintenance an d a djustment
6-24
6
EAU22734
Chan gin g the brake flui dHave a Yamaha dealer change the
brake fluid every 2 years. In addition,
have the seals of the master cylinders
and brake calipers, as well as the brake
hoses replaced at the intervals listed
below or sooner if they are damaged or
leaking.
 Brake seals: every 2 years
 Brake hoses: every 4 years
EAU22762
Drive chain slackThe drive chain slack should be
checked before each ride and adjusted
if necessary.
EAU74253
To check the drive chain slack
1. Place the motorcycle on the side- stand.TIPWhen checking and adjusting the drive
chain slack, there should be no weight
on the motorcycle.2. Shift the transmission into theneutral 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 lea d to chain slip-
pa ge or breakag e. To prevent
this from occurrin g, keep the
d rive chain slack within the
specifie d limits.
[ECA10572]
EAU3431B
To adjust the drive chain slack
Consult a Yamaha dealer before ad-
justing the drive chain slack. 1. Loosen the axle nut and the lock- nut on each side of the swingarm.
1. Drive chain slackZAUM1604
1
Drive chain slack:30.0–40.0 mm (1.18–1.57 in)
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Periodic maintenance an d a djustment
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2. To tighten the drive chain, turn the drive chain slack adjusting bolt on
each side of the swingarm in di-
rection (a). To loosen the drive
chain, turn the adjusting bolt on
each side of the swingarm in di-
rection (b), and then push the rear
wheel forward.
TIPUsing the alignment marks on each
side of the swingarm, make sure that
both drive chain pullers are in the same
position for proper wheel alignment.
3. Tighten the axle nut, then the lock-nuts to their specified torques.
4. Make sure that the drive chain pullers are in the same position,
the drive chain slack is correct,
and the drive chain moves
smoothly.
EAU23026
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 b e lubricate d
after washin g the motorcycle, ri din g
in the rain or ri din g in wet areas.1. Clean the drive chain with kero-
sene and a small soft brush.
NOTICE: To prevent d amaging
the O-rin gs, do not clean the
d rive chain with steam cleaners,
hi gh-pressure washers or inap-
propriate solvents.
[ECA11122]
2. Wipe the drive chain dry.
3. Thoroughly lubricate the drive chain with a special O-ring chain
lubricant. NOTICE: Do not use
en gine oil or any other lu bri-
cants for the drive chain, as they
1. Drive chain slack adjusting bolt
2. Axle nut
3. Alignment marks
4. LocknutZAUM1605
321
4
(b)
(a)
Ti
ghtenin g torques:
Axle nut: 85 N·m (8.5 kgf·m, 63 lb·ft)
Locknut:
15 N·m (1.5 kgf·m, 11 lb·ft)
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Periodic maintenance an d a djustment
6-26
6 may contain su
bstances that
coul d damag e the O-rin gs.
[ECA11112] EAU23098
Checkin
g an d lu bricatin g the
cab lesThe operation of all control cables and
the condition of the cables should be
checked before each ride, and the ca-
bles and cable ends should be lubri-
cated if necessary. If a cable is
damaged or does not move smoothly,
have a Yamaha dealer check or re-
place it. WARNING! Dama ge to the
outer housin g of cab les may result
in internal rustin g an d cause inter-
ference with cab le movement. Re-
place damag ed cab les as soon as
possi ble to prevent unsafe con di-
tions.
[EWA10712] EAU23115
Checkin
g an d lu bricatin g the
throttle grip an d ca bleThe operation of the throttle grip
should be checked before each ride. In
addition, the cable should be lubricat-
ed by a Yamaha dealer at the intervals
specified in the periodic maintenance
chart.
The throttle cable is equipped with a
rubber cover. Make sure that the cover
is securely installed. Even though the
cover is installed correctly, it does not
completely protect the cable from wa-
ter entry. Therefore, use care not to
pour water directly onto the cover or
cable when washing the vehicle. If the
cable or cover becomes dirty, wipe
clean with a moist cloth.
Recommen ded lu bricant:
Yamaha cable lubricant or other
suitable cable lubricant
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Periodic maintenance an d a djustment
6-27
6
EAU44276
Checkin g an d lu bricatin g the
b rake an d shift pe dalsThe operation of the brake and shift
pedals should be checked before each
ride, and the pedal pivots should be lu-
bricated if necessary.
Brake pe dal
Shift pe dal
EAU23144
Checkin g an d lu bricatin g the
b rake an d clutch leversThe operation of the brake and clutch
levers should be checked before each
ride, and the lever pivots should be lu-
bricated if necessary.
Brake lever
Clutch lever
Recommen ded lu bricant:
Lithium-soap-based grease
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Periodic maintenance an d a djustment
6-28
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EAU23203
Checkin g an d lu bricatin g the
si destan dThe operation of the sidestand should
be checked before each ride, and the
sidestand pivot and metal-to-metal
contact surfaces should be lubricated
if necessary.
WARNING
EWA10732
If the si destan d d oes not move up
an d d own smoothly, have a Yamaha
d ealer check or repair it. Otherwise,
the si destan d coul d contact the
g roun d an d d istract the operator, re-
sultin g in a possi ble loss of control.
EAU23252
Lub ricatin g the rear suspen-
sionThe pivoting points of the rear suspen-
sion must be lubricated by a Yamaha
dealer at the intervals specified in the
periodic maintenance and lubrication
chart.
Recommen ded lu bricants:
Brake lever:
Silicone grease
Clutch lever:
Lithium-soap-based grease
Recommen ded lu bricant:
Lithium-soap-based grease
Recommen ded lu bricant:
Lithium-soap-based grease
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