2008 YAMAHA YBR125 engine

INSTRUMENT AND CONTROL FUNCTIONS
3-4
3
EAU12347
Handlebar switches Left
Right
EAU12400
Dimmer switch“/”
Set this switch to“” for the high
beam and to“” for the low beam.
EAU12460
Turn signal switch“/”
To signal a right-hand turn, push this
switch to“”. To signal a left-hand
turn, push this switch to“”. When re-
leased, the switch returns to the center
position. To cancel the turn signal
lights, push the switch in after it has re-
turned to the center position.
EAU12500
Horn switch“”
Press this switch to sound the horn.
EAU12710
Start switch“”
Push this switch to crank the engine
with the starter.CAUTION:
ECA10050
See page 5-1 for starting instruc-tions prior to starting the engine.
EAU41700
The engine trouble warning light will
come on when the key is turned to “ON”
and the start switch is pushed, but this
does not indicate a malfunction.
1. Dimmer switch“/”
2. Turn signal switch“/”
3. Horn switch“”
1. Start switch“”U27SE0E0.book Page 4 Friday, February 22, 2008 8:54 AM

INSTRUMENT AND CONTROL FUNCTIONS
3-5
3
EAU12820
Clutch lever The clutch lever is located at the left
handlebar grip. To disengage the
clutch, pull the lever toward the handle-
bar grip. To engage the clutch, release
the lever. The lever should be pulled
rapidly and released slowly for smooth
clutch operation.
The clutch lever is equipped with a
clutch switch, which is part of the igni-
tion circuit cut-off system. (See page
3-10.)
EAU12870
Shift pedal The shift pedal is located on the left
side of the engine and is used in com-
bination with the clutch lever when
shifting the gears of the 5-speed con-
stant-mesh transmission equipped on
this motorcycle.
EAU12890
Brake lever The brake lever is located at the right
handlebar grip. To apply the front
brake, pull the lever toward the handle-
bar grip.
1. Clutch lever
1. Shift pedal
1
1. Brake lever
1
U27SE0E0.book Page 5 Friday, February 22, 2008 8:54 AM

INSTRUMENT AND CONTROL FUNCTIONS
3-7
3
EAU13220
Fuel Make sure that there is sufficient fuel in
the tank. When refueling, be sure to in-
sert the pump nozzle into the fuel tank
filler hole and to fill the tank to the bot-
tom of the filler tube as shown.
WARNING
EWA10880


Do not overfill the fuel tank, oth-
erwise it may overflow when the
fuel warms up and expands.


Avoid spilling fuel on the hot en-gine.
CAUTION:
ECA10070
Immediately wipe off spilled fuel
with a clean, dry, soft cloth, since
fuel may deteriorate painted surfac-es or plastic parts.
EAU13320
CAUTION:
ECA11400
Use only unleaded gasoline. The use
of leaded gasoline will cause severe
damage to internal engine parts,
such as the valves and piston rings,as well as to the exhaust system.
Your Yamaha engine has been de-
signed to use regular unleaded gaso-
line with a research octane number of
91 or higher. If knocking (or pinging) oc-
curs, use a gasoline of a different brandor premium unleaded fuel. Use of un-
leaded fuel will extend spark plug life
and reduce maintenance costs.
1. Fuel tank filler tube
2. Fuel level
1
2
Recommended fuel:
REGULAR UNLEADED GASOLINE
ONLY
Fuel tank capacity:
12.0 L (3.17 US gal, 2.64 Imp.gal)
Fuel reserve amount:
3.0 L (0.79 US gal, 0.66 Imp.gal)
U27SE0E0.book Page 7 Friday, February 22, 2008 8:54 AM

INSTRUMENT AND CONTROL FUNCTIONS
3-8
3
EAU13443
Catalytic converters This vehicle is equipped with catalytic
converters in the exhaust system.
WARNING
EWA10860
The exhaust system is hot after op-
eration. Make sure that the exhaust
system has cooled down before do-ing any maintenance work.CAUTION:
ECA16490
The following precautions must be
observed to prevent a fire hazard or
other damages.

Use only unleaded gasoline.
The use of leaded gasoline will
cause unrepairable damage to
the catalytic converters.


Never park the vehicle near pos-
sible fire hazards such as grass
or other materials that easily
burn.


Do not allow the engine to idletoo long.
EAU43150
Kickstarter If the engine fails to start by pushing the
start switch, try to start it by using the
kickstarter. To start the engine, fold out
the kickstarter lever, move it down light-
ly with your foot until the gears engage,
and then push it down smoothly but
forcefully. This model is equipped with
a primary kickstarter, allowing the en-
gine to be started in any gear if the
clutch is disengaged and the sidestand
is up. However, shifting the transmis-
sion into the neutral position before
starting is recommended.
EAU14880
Adjusting the shock absorber
assemblies Each shock absorber assembly is
equipped with a spring preload adjust-
ing ring.CAUTION:
ECA10100
Never attempt to turn an adjusting
mechanism beyond the maximum orminimum settings.
1. Kickstarter lever
1. Spring preload adjusting ring
2. Position indicator
(a)(b)
2
1
U27SE0E0.book Page 8 Friday, April 11, 2008 4:46 PM

INSTRUMENT AND CONTROL FUNCTIONS
3-10
3below and have a Yamaha dealer re-
pair it if it does not function proper-
ly.
EAU43161
Ignition circuit cut-off system The ignition circuit cut-off system (com-
prising the sidestand switch, clutch
switch and neutral switch) has the fol-
lowing functions.

It prevents starting when the trans-
mission is in gear and the side-
stand is up, but the clutch lever is
not pulled.


It prevents starting when the trans-
mission is in gear and the clutch le-
ver is pulled, but the sidestand is
still down.


It cuts the running engine when the
transmission is in gear and the sid-
estand is moved down.
Periodically check the operation of the
ignition circuit cut-off system according
to the following procedure.WARNING
EWA10260


The vehicle must be placed on
the centerstand during this in-
spection.


If a malfunction is noted, have a
Yamaha dealer check the sys-tem before riding.
U27SE0E0.book Page 10 Friday, February 22, 2008 8:54 AM

INSTRUMENT AND CONTROL FUNCTIONS
3-11
3
With the engine turned off:
1. Move the sidestand down.
2. Turn the key on.
3. Shift the transmission into the neutral position.
4. Push the start switch or push the kickstarter lever down.
Does the engine start?
With the engine still running:
5. Move the sidestand up.
6. Keep the clutch lever pulled.
7. Shift the transmission into gear.
8. Move the sidestand down.
Does the engine stall?
After the engine has stalled:
9. Move the sidestand up.
10. Keep the clutch lever pulled.
11. Push the start switch or push the kickstarter lever down.
Does the engine start?
The system is OK. The motorcycle can be ridden.The neutral switch may be defective.
The motorcycle should not be ridden until
checked by a Yamaha dealer.
The sidestand switch may be defective.
The motorcycle should not be ridden until
checked by a Yamaha dealer.
The clutch switch may be defective.
The motorcycle should not be ridden until
checked by a Yamaha dealer.
YES NO YES NO YES NO
U27SE0E0.book Page 11 Friday, February 22, 2008 8:54 AM

PRE-OPERATION CHECKS
4-2
4
EAU15605
Pre-operation check list
ITEM CHECKS PAGE
FuelCheck fuel level in fuel tank.
Refuel if necessary.
Check fuel line for leakage.3-7
Engine oilCheck oil level in engine.
If necessary, add recommended oil to specified level.
Check vehicle for oil leakage.6-9
Front brakeCheck operation.
If soft or spongy, have Yamaha dealer bleed hydraulic system.
Check brake pads for wear.
Replace if necessary.
Check fluid level in reservoir.
If necessary, add recommended brake fluid to specified level.
Check hydraulic system for leakage.6-19, 6-19
Rear brakeCheck operation.
Check pedal free play.
Adjust if necessary.6-17, 6-19
ClutchCheck operation.
Lubricate cable if necessary.
Check lever free play.
Adjust if necessary.6-16
Throttle gripMake sure that operation is smooth.
Check cable free play.
If necessary, have Yamaha dealer adjust cable free play and lubricate cable and
grip housing.6-12, 6-23
Control cablesMake sure that operation is smooth.
Lubricate if necessary.6-23
Drive chainCheck chain slack.
Adjust if necessary.
Check chain condition.
Lubricate if necessary.6-21, 6-22
U27SE0E0.book Page 2 Friday, February 22, 2008 8:54 AM

OPERATION AND IMPORTANT RIDING POINTS
5-1
5
EAU15950
WARNING
EWA10270


Become thoroughly familiar
with all operating controls and
their functions before riding.
Consult a Yamaha dealer re-
garding any control or function
that you do not thoroughly un-
derstand.


Never start the engine or oper-
ate it in a closed area for any
length of time. Exhaust fumes
are poisonous, and inhaling
them can cause loss of con-
sciousness and death within a
short time. Always make sure
that there is adequate ventila-
tion.


Before starting out, make sure
that the sidestand is up. If the
sidestand is not raised com-
pletely, it could contact the
ground and distract the opera-
tor, resulting in a possible lossof control.
EAU45310
NOTE:This 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 “OFF” and then to “ON”. Fail-
ing to do so will prevent the engine from
starting even though the engine willcrank when pushing the start switch.
EAU43181
Starting the engine In 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 sid-
estand up.WARNING
EWA10290


Before starting the engine,
check the function of the igni-
tion circuit cut-off system ac-
cording to the procedure
described on page 3-10.


Never ride with the sidestanddown.
1. Turn the key to “ON”.
2. Shift the transmission into the neu-
tral position.
NOTE:When the transmission is in the neutral
position, the neutral indicator light
should be on, otherwise have a
Yamaha dealer check the electrical cir-cuit.
U27SE0E0.book Page 1 Friday, February 22, 2008 8:54 AM