2008 YAMAHA YBR125 maintenance

PERIODIC MAINTENANCE AND MINOR REPAIR
6-13
6 2. To increase the throttle cable free
play, turn the adjusting nut in direc-
tion (a). To decrease the throttle
cable free play, turn the adjusting
nut in direction (b).
3. Tighten the locknut.
EAU21401
Valve clearance The valve clearance changes with use,
resulting in improper air-fuel mixture
and/or engine noise. To prevent this
from occurring, the valve clearance
must be adjusted by a Yamaha dealer
at the intervals specified in the periodic
maintenance and lubrication chart.
EAU21561
Tires To maximize the performance, durabil-
ity, and safe operation of your motor-
cycle, note the following points
regarding the specified tires.
Tire air pressure
The tire air pressure should be checked
and, if necessary, adjusted before each
ride.
WARNING
EWA10500


The tire air pressure must be
checked and adjusted on cold
tires (i.e., when the temperature
of the tires equals the ambient
temperature).


The tire air pressure must be ad-
justed in accordance with the
riding speed and with the total
weight of rider, passenger, car-
go, and accessories approvedfor this model.
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PERIODIC MAINTENANCE AND MINOR REPAIR
6-14
6
WARNING
EWA11020
Because loading has an enormous
impact on the handling, braking,
performance and safety characteris-
tics of your motorcycle, you should
keep the following precautions in
mind.

NEVER OVERLOAD THE
MOTORCYCLE! Operation of an
overloaded motorcycle may re-
sult in tire damage, loss of con-
trol, or severe injury. Make sure
that the total weight of rider,passenger, cargo, and accesso-
ries does not exceed the speci-
fied maximum load for the
vehicle.


Do not carry along loosely
packed items, which can shift
during a ride.


Securely pack the heaviest
items close to the center of the
motorcycle and distribute the
weight evenly on both sides.


Adjust the suspension and tire
air pressure with regard to the
load.


Check the tire condition and airpressure before each ride.Tire inspection
The tires must be checked before each
ride. If the center tread depth reaches
the specified limit, if the tire has a nail or
glass fragments in it, or if the sidewall is
cracked, have a Yamaha dealer re-
place the tire immediately.
NOTE:The tire tread depth limits may differ
from country to country. Always complywith the local regulations.
Tire air pressure (measured on cold
tires):
0–90 kg (0–198 lb):
Front:
175 kPa (1.75 kgf/cm², 25 psi)
Rear:
200 kPa (2.00 kgf/cm², 29 psi)
90–190 kg (198–419 lb):
Front:
175 kPa (1.75 kgf/cm², 25 psi)
Rear:
280 kPa (2.80 kgf/cm², 41 psi)
Maximum load*:
190 kg (419 lb)
* Total weight of rider, passenger, car-
go and accessories
1. Tire sidewall
2. Tire tread depthMinimum tire tread depth (front and
rear):
1.6 mm (0.06 in)
U27SE0E0.book Page 14 Friday, February 22, 2008 8:54 AM

PERIODIC MAINTENANCE AND MINOR REPAIR
6-15
6 Tire information
This motorcycle is equipped with cast
wheels and tubeless tires.
WARNING
EWA10460


The front and rear tires should
be of the same make and de-
sign, otherwise the handling
characteristics of the vehicle
cannot be guaranteed.


After extensive tests, only the
tires listed below have been ap-
proved for this model byYamaha Motor Co., Ltd.
WARNING
EWA10470


Have a Yamaha dealer replace
excessively worn tires. Besides
being illegal, operating the vehi-
cle with excessively worn tires
decreases riding stability and
can lead to loss of control.


The replacement of all wheel
and brake related parts, includ-
ing the tires, should be left to a
Yamaha dealer, who has the
necessary professional knowl-edge and experience.
EAU21960
Cast wheels To maximize the performance, durabil-
ity, and safe operation of your vehicle,
note the following points regarding the
specified wheels.

The wheel rims should be checked
for cracks, bends or warpage be-
fore each ride. If any damage is
found, have a Yamaha dealer re-
place the wheel. Do not attempt
even the smallest repair to the
wheel. A deformed or cracked
wheel must be replaced.


The wheel should be balanced
whenever either the tire or wheel
has been changed or replaced. An
unbalanced wheel can result in
poor performance, adverse han-
dling characteristics, and a short-
ened tire life.


Ride at moderate speeds after
changing a tire since the tire sur-
face must first be “broken in” for it
to develop its optimal characteris-
tics.
Front tire:
Size:
3.00-18 47P
Manufacturer/model:
CHENG SHIN/C-6039
Rear tire:
Size:
3.50-16 58P
Manufacturer/model:
CHENG SHIN/C-289
U27SE0E0.book Page 15 Friday, February 22, 2008 8:54 AM

PERIODIC MAINTENANCE AND MINOR REPAIR
6-16
6
EAU22032
Adjusting the clutch lever free
play The clutch lever free play should mea-
sure 10.0–15.0 mm (0.39–0.59 in) as
shown. Periodically check the clutch le-
ver free play and, if necessary, adjust it
as follows.
1. Loosen the locknut at the clutch le-
ver.
2. To increase the clutch lever free
play, turn the clutch lever free play
adjusting bolt in direction (a). To
decrease the clutch lever free play,
turn the adjusting bolt in direction
(b).3. If the specified clutch lever free
play could be obtained as de-
scribed above, tighten the locknut
and skip the rest of the procedure,
otherwise, proceed as follows.
4. Fully turn the adjusting bolt in di-
rection (a) to loosen the clutch ca-
ble.
5. Loosen the locknut further down
the clutch cable.
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 direction
(b).7. Tighten both locknuts.1. Locknut (clutch lever)
2. Clutch lever free play adjusting bolt
3. Clutch lever free play
1. Locknut (clutch cable)
2. Clutch lever free play adjusting nut (clutch
cable)
1
2
(a) (b)
U27SE0E0.book Page 16 Friday, February 22, 2008 8:54 AM

PERIODIC MAINTENANCE AND MINOR REPAIR
6-17
6
EAUT1221
Checking the front brake lever
free play The brake lever free play should mea-
sure 0.0–7.0 mm (0.00–0.28 in) as
shown. Periodically check the brake le-
ver free play and, if necessary, have a
Yamaha dealer check the brake sys-
tem.
WARNING
EWA10641
An incorrect brake lever free play in-
dicates a hazardous condition in the
brake system. Do not operate the ve-
hicle until the brake system has
been checked or repaired by aYamaha dealer.
EAU39812
Adjusting the brake pedal free
play The brake pedal free play should mea-
sure 20.0–30.0 mm (0.79–1.18 in) at
the brake pedal end as shown. Period-
ically check the brake pedal free play
and, if necessary, adjust it as follows.
To increase the brake pedal free play,
turn the adjusting nut at the brake rod in
direction (a). To decrease the brake
pedal free play, turn the adjusting nut in
direction (b).
WARNING
EWA10680


After adjusting the drive chain
slack or removing and installing
the rear wheel, always check the
brake pedal free play.


If proper adjustment cannot be
obtained as described, have a
Yamaha dealer make this ad-
justment.


After adjusting the brake pedal
free play, check the operation ofthe brake light.
1. Brake lever free play
1. Brake pedal free play
1. Brake pedal free play adjusting nut
1(a)
(b)
U27SE0E0.book Page 17 Friday, February 22, 2008 8:54 AM

PERIODIC MAINTENANCE AND MINOR REPAIR
6-18
6
EAU44820
Checking the shift pedal The operation of the shift pedal should
be checked before each ride. If opera-
tion is not smooth, have a Yamaha
dealer check the vehicle.
EAU22291
Adjusting the rear brake light
switch The rear brake light switch, which is ac-
tivated by the brake pedal, is properly
adjusted when the brake light comes
on just before braking takes effect. If
necessary, adjust the brake light switch
as follows.
1. Remove panel B. (See page 6-6.)
2. Turn the adjusting nut while hold-
ing the rear brake light switch in
place. To make the brake light
come on earlier, turn the adjusting
nut in direction (a). To make the
brake light come on later, turn the
adjusting nut in direction (b).3. Install the panel.1. Rear brake light switch
2. Rear brake light switch adjusting nut
U27SE0E0.book Page 18 Friday, February 22, 2008 8:54 AM

PERIODIC MAINTENANCE AND MINOR REPAIR
6-19
6
EAU22380
Checking the front brake pads
and rear brake shoes The front brake pads and the rear brake
shoes must be checked for wear at the
intervals specified in the periodic main-
tenance and lubrication chart.
EAU22430
Front brake pads
Each front 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 wearindicator grooves have almost disap-
peared, have a Yamaha dealer replace
the brake pads as a set.
EAU43170
Rear brake shoes
The rear brake is provided with a wear
indicator, which allows you to check the
brake shoe wear without having to dis-
assemble the brake. To check the
brake shoe wear, check the position of
the wear indicator while applying the
brake. If a brake shoe has worn to the
point that the wear indicator reaches
the wear limit mark, have a Yamaha
dealer replace the brake shoes as a
set.
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:
1. Brake pad wear indicator groove
1. Brake shoe wear limit mark
2. Brake shoe wear indicator
1
2
1. Minimum level mark
U27SE0E0.book Page 19 Friday, February 22, 2008 8:54 AM

PERIODIC MAINTENANCE AND MINOR REPAIR
6-20
6


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.
NOTE:If DOT 4 is not available, DOT 3 can beused.

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.
EAU22720
Changing the brake fluid Have a Yamaha dealer change the
brake fluid at the intervals specified in
the NOTE after the periodic mainte-
nance and lubrication chart. In addition,
have the oil seals of the brake master
cylinder and caliper as well as the
brake hose replaced at the intervals
listed below or whenever they are dam-
aged or leaking.

Oil seals: Replace every two
years.


Brake hose: Replace every four
years.
Recommended brake fluid:
DOT 4
U27SE0E0.book Page 20 Friday, February 22, 2008 8:54 AM