2010 YAMAHA YBR125 lock

PERIODIC MAINTENANCE AND ADJUSTMENT
6-19
6
EAU37001
Checking the front brake fluid
level Insufficient brake fluid may allow air to
enter the brake system, possibly caus-
ing it to become ineffective.
Before riding, check that the brake fluid
is above the minimum level mark and
replenish if necessary. A low brake fluid
level may indicate worn brake pads
and/or brake system leakage. If the
brake fluid level is low, be sure to check
the brake pads for wear and the brake
system for leakage.
Observe these precautions:


When checking the fluid level,
make sure that the top of the mas-
ter cylinder is level by turning the
handlebars.


Use only the recommended quality
brake fluid, otherwise the rubber
seals may deteriorate, causing
leakage and poor braking perfor-
mance.
TIPIf DOT 4 is not available, DOT 3 can be
used.

Refill with the same type of brake
fluid. Mixing fluids may result in a
harmful chemical reaction and
lead to poor braking performance.


Be careful that water does not en-
ter the master cylinder when refill-
ing. Water will significantly lower
the boiling point of the fluid and
may result in vapor lock.


Brake fluid may deteriorate paint-
ed surfaces or plastic parts. Al-
ways clean up spilled fluid
immediately.


As the brake pads wear, it is nor-
mal for the brake fluid level to grad-
ually go down. However, if the
brake fluid level goes down sud-
denly, have a Yamaha dealer
check the cause.
1. Minimum level mark
Recommended brake fluid:
DOT 4
U51DE0E0.book Page 19 Monday, November 2, 2009 10:34 AM

PERIODIC MAINTENANCE AND ADJUSTMENT
6-20
6
EAU22721
Changing the brake fluid Have a Yamaha dealer change the
brake fluid at the intervals specified in
the TIP after the periodic maintenance
and lubrication chart. In addition, have
the oil seals of the brake master cylin-
der and caliper as well as the brake
hose replaced at the intervals listed be-
low or whenever they are damaged or
leaking.

Oil seals: Replace every two
years.


Brake hose: Replace every four
years.
EAU22760
Drive chain slack The drive chain slack should be
checked before each ride and adjusted
if necessary.
EAU22793
To check the drive chain slack
1. Place the motorcycle on the cen-
terstand.
2. Shift the transmission into the neu-
tral position.
3. Spin the rear wheel several times
to locate the tightest portion of the
drive chain.
4. Measure the drive chain slack as
shown.5. If the drive chain slack is incorrect,
adjust it as follows.
EAUP0060
To adjust the drive chain slack
1. Remove the brake torque rod cot-
ter pin, and then loosen the brake
pedal free play adjusting nut,
brake torque rod nut, and axle nut.
2. Loosen the drive chain puller lock-
nut at each end of the swingarm.
1. Drive chain slack
Drive chain slack:
20.0–30.0 mm (0.79–1.18 in)1. Drive chain slack adjusting bolt
2. Drive chain puller locknut
3. Axle nut
4. Brake torque rod nut
5. Brake torque rod cotter pin
6. Brake pedal free play adjusting nut
1
2
34
5
6
U51DE0E0.book Page 20 Monday, November 2, 2009 10:34 AM

PERIODIC MAINTENANCE AND ADJUSTMENT
6-21
6 3. To tighten the drive chain, turn the
drive chain slack adjusting bolt at
each end of the swingarm in direc-
tion (a). To loosen the drive chain,
turn the adjusting bolt at each end
of the swingarm in direction (b),
and then push the rear wheel for-
ward. NOTICE: Improper drive
chain slack will overload the en-
gine as well as other vital parts
of the motorcycle and can lead
to chain slippage or breakage.
To prevent this from occurring,
keep the drive chain slack with-
in the specified limits.
[ECA10571]
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.
4. Tighten both locknuts, and then
tighten the axle nut and brake
torque rod nut to their specified
torques.
5. Insert a new cotter pin.
6. Adjust the brake pedal free play.
(See page 6-16.)
WARNING
EWA10660
After adjusting the brake pedal free
play, check the operation of the
brake light.
1. Alignment marks
2. Drive chain puller
3. Drive chain puller locknut
4. Drive chain slack adjusting bolt
Tightening torques:
Axle nut:
80 Nm (8.0 m·kgf, 58 ft·lbf)
Brake torque rod nut:
19 Nm (1.9 m·kgf, 14 ft·lbf)
1
2
3
4
U51DE0E0.book Page 21 Monday, November 2, 2009 10:34 AM

PERIODIC MAINTENANCE AND ADJUSTMENT
6-29
6
EAU23783
Replacing the headlight bulb This model is equipped with a quartz
bulb headlight. If the headlight bulb
burns out, replace it as follows.NOTICE
ECA10650
Take care not to damage the follow-
ing parts:

Headlight bulb
Do not touch the glass part of
the headlight bulb to keep it free
from oil, otherwise the transpar-
ency of the glass, the luminosity
of the bulb, and the bulb life will
be adversely affected. Thor-
oughly clean off any dirt and fin-
gerprints on the headlight bulb
using a cloth moistened with al-
cohol or thinner.


Headlight lens
Do not affix any type of tinted
film or stickers to the headlight
lens.
Do not use a headlight bulb of a
wattage higher than specified.
1. Remove the headlight unit by re-
moving the screws.
2. Disconnect the headlight coupler,
and then remove the bulb cover.3. Remove the headlight bulb holder
by turning it counterclockwise, and
then remove the burnt-out bulb.
4. Place a new headlight bulb into po-
sition, and then secure it with the
bulb holder.1. Do not touch the glass part of the bulb.
1. Screw
1
1. Headlight coupler
2. Bulb cover
1. Headlight bulb holder1
2
1
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PERIODIC MAINTENANCE AND ADJUSTMENT
6-30
65. Install the headlight bulb cover,
and then connect the coupler.
6. Install the headlight unit by install-
ing the screws.
7. Have a Yamaha dealer adjust the
headlight beam if necessary.
EAU24133
Replacing the tail/brake light
bulb 1. Remove the tail/brake light lens by
removing the screws.
2. Remove the burnt-out bulb by
pushing it in and turning it counter-
clockwise.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
screws. NOTICE: Do not over-
tighten the screws, otherwise
the lens may break.
[ECA10681]
1. Screw
1. Tail/brake light bulb
U51DE0E0.book Page 30 Monday, November 2, 2009 10:34 AM

PERIODIC MAINTENANCE AND ADJUSTMENT
6-31
6
EAU24204
Replacing a turn signal light
bulb 1. Remove the turn signal light lens
by removing the screw.
2. Remove the burnt-out bulb by
pushing it in and turning it counter-
clockwise.
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-
tighten the screw, otherwise the
lens may break.
[ECA11191]EAU45222
Replacing an auxiliary light
bulb If the auxiliary light bulb burns out, re-
place it as follows.
1. Remove the headlight unit. (See
page 6-29.)
2. Remove the auxiliary light socket
(together with the bulb) by pulling it
out.
3. Remove the burnt-out bulb by pull-
ing it out.4. Insert a new bulb into the socket.
5. Install the auxiliary light socket (to-
gether with the bulb) by pushing it
in.
6. Install the headlight unit.
1. Screw
1
1. Auxiliary light bulb socket
1
1. Auxiliary light bulb
1
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PERIODIC MAINTENANCE AND ADJUSTMENT
6-34
63. Place the motorcycle on the cen-
terstand.
4. Remove the brake pedal free play
adjusting nut, and then disconnect
the brake rod from the brake cam-
shaft lever.5. Loosen the drive chain puller lock-
nut and the drive chain slack ad-
justing bolt on both ends of the
swingarm.6. Remove the axle nut, and then pull
the wheel axle out.
7. Push the wheel forward, and then
remove the drive chain from the
rear sprocket.
TIPThe drive chain does not need to be
disassembled in order to remove and
install the wheel.8. Remove the wheel.
EAU37193
To install the rear wheel
1. Install the wheel by inserting the
wheel axle from the left-hand side.
2. Install the drive chain onto the rear
sprocket.
3. Install the axle nut.
4. Install the brake rod onto the brake
camshaft lever, and then install the
brake pedal free play adjusting nut
onto the brake rod.
5. Connect the brake torque rod to
the brake shoe plate by installing
the bolt and nut.
6. Adjust the drive chain slack. (See
page 6-20.)
1. Axle nut
2. Brake torque rod
3. Brake torque rod nut and bolt
4. Brake torque rod cotter pin
13
2
4
1. Brake pedal free play adjusting nut
2. Brake rod
3. Brake camshaft lever
1. Wheel axle
2. Drive chain puller locknut
3. Drive chain slack adjusting bolt
3
1
2
U51DE0E0.book Page 34 Monday, November 2, 2009 10:34 AM

INDEX
AAir filter element, cleaning .................... 6-10
Auxiliary light bulb, replacing ................ 6-31BBattery .................................................. 6-26
Brake and clutch levers, checking and
lubricating ........................................... 6-23
Brake fluid, changing ............................ 6-20
Brake fluid level, checking .................... 6-19
Brake lever ............................................. 3-5
Brake light switches .............................. 6-17
Brake pads and shoes, checking.......... 6-18
Brake pedal ............................................ 3-6
Brake pedal, checking and
lubricating ........................................... 6-24
Brake pedal free play, adjusting ........... 6-16CCables, checking and lubricating .......... 6-22
Care ........................................................ 7-1
Carrier................................................... 3-10
Catalytic converters ................................ 3-8
Centerstand and sidestand, checking
and lubricating .................................... 6-24
Clutch lever............................................. 3-5
Clutch lever free play, adjusting ........... 6-15DDimmer switch ........................................ 3-4
Drive chain, cleaning and lubricating .... 6-22
Drive chain slack .................................. 6-20EEngine break-in ...................................... 5-3
Engine idling speed, checking .............. 6-12
Engine oil ................................................ 6-9
Engine trouble warning light ................... 3-2
FFront brake lever free play, checking .... 6-16
Front fork, checking...............................6-25
Fuel ......................................................... 3-7
Fuel consumption, tips for reducing ........ 5-3
Fuel gauge .............................................. 3-4
Fuel tank cap........................................... 3-6
Fuse, replacing...................................... 6-28HHandlebar switches ................................. 3-4
Headlight bulb, replacing....................... 6-29
High beam indicator light......................... 3-2
Horn switch ............................................. 3-4IIdentification numbers ............................. 9-1
Ignition circuit cut-off system ................. 3-11
Indicator and warning lights .................... 3-2KKickstarter ............................................... 3-9MMain switch/steering lock ........................ 3-1
Maintenance and lubrication, periodic..... 6-3
Maintenance, emission control system ... 6-2
Matte color, caution .................................7-1
Model label .............................................. 9-1NNeutral indicator light .............................. 3-2PPanels, removing and installing .............. 6-6
Parking ....................................................5-4
Part locations .......................................... 2-1SSafety information ...................................1-1
Self-diagnosis device .............................. 3-3Shifting .................................................... 5-2
Shift pedal ............................................... 3-5
Shift pedal, checking............................. 6-17
Shock absorber assemblies, adjusting ... 3-9
Sidestand .............................................. 3-10
Spark plug, checking .............................. 6-7
Specifications.......................................... 8-1
Speedometer unit ................................... 3-3
Starting the engine.................................. 5-1
Start switch ............................................. 3-4
Steering, checking ................................ 6-26
Storage ................................................... 7-3
Swingarm pivots, lubricating ................. 6-25
TTachometer............................................. 3-3
Tail/brake light bulb, replacing .............. 6-30
Throttle cable free play, checking ......... 6-12
Throttle grip and cable, checking and
lubricating ........................................... 6-23
Tires ...................................................... 6-13
Tool kit .................................................... 6-1
Troubleshooting .................................... 6-35
Troubleshooting chart ........................... 6-36
Turn signal indicator lights ...................... 3-2
Turn signal light bulb, replacing ............ 6-31
Turn signal switch ................................... 3-4VValve clearance .................................... 6-13
Vehicle identification number .................. 9-1WWheel bearings, checking..................... 6-26
Wheel (front) ......................................... 6-32
Wheel (rear) .......................................... 6-33
Wheels .................................................. 6-15
U51DE0E0.book Page 1 Monday, November 2, 2009 10:34 AM