2017 YAMAHA YS125 engine

Instrument and control functions
3-4
3
O
dometer an d tripmeter
The odometer shows the total distance
traveled by the vehicle.
The tripmeter shows the distance trav-
eled since it was last reset.
TIP The odometer will lock at 999999.
 The tripmeter will reset and conti-
nue counting after 9999.9 is
reached.Pushing the “RESET/SELECT” button
switches the display between the
odometer “ODO” and the tripmeter
“TRIP”. To reset the tripmeter, select it by
pushing the “RESET/SELECT” button,
and then push the “RESET/SELECT”
button for one second.
Tachometer
The tachometer allows the rider to
monitor the engine speed and keep it
within the ideal power range.
NOTICE
ECA10032
Do not operate the en
gine in the ta-
chometer red zone.
Re d zone: 9000 r/min an d a bove
Fuel meter
The fuel meter indicates the amount of
fuel in the fuel tank. The display seg-
ments of the fuel meter disappear from
“F” (full) towards “E” (empty) as the fuel
level decreases. When the last seg-
ment of the fuel meter and the fuel level
warning indicator “ ” start flashing,
refuel as soon as possible.TIPIf a problem is detected in the fuel me-
ter electrical circuit, all the display seg-
ments and the fuel level warning
indicator “ ” start flashing. If this oc-
curs, have a Yamaha dealer check the
electrical circuit.
1. Odometer/tripmeter
1
1. Tachometer
2. Tachometer red zone1 2
1. Fuel level warning indicator “ ”
2. Fuel meter
1
2
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Instrument and control functions
3-6
3
EAU12713
Start switch “ ”
Push this switch to crank the engine
with the starter. See page 5-1 for start-
ing instructions prior to starting the en-
gine.
EAU12822
Clutch leverThe clutch lever is located on the left
side of the handlebar. To disengage
the clutch, pull the lever toward the
handlebar 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
3-13.)
EAU12872
Shift pe dalThe shift pedal is located on the left
side of the motorcycle and is used in
combination with the clutch lever when
shifting the gears of the 5-speed con-
stant-mesh transmission equipped on
this motorcycle.
1. Clutch lever
1
1. Shift pedal
1
UBT4E0E0.book Page 6 Thursday, November 17, 2016 10:55 AM

Instrument and control functions
3-8
3
EAU13003
Fuel tank capTo remove the fuel tank cap
Insert the key into the lock and turn it
1/4 turn clockwise. The lock will be re-
leased and the fuel tank cap can be re-
moved.
To install the fuel tank cap
1. Push the fuel tank cap into posi- tion with the key inserted in the
lock.
2. Turn the key counterclockwise to the original position, and then re-
move it.
TIPThe fuel tank cap cannot be installed
unless the key is in the lock. In addi-
tion, the key cannot be removed if the
cap is not properly installed and
locked.
WARNING
EWA11142
Make sure that the fuel tank cap is
properly installe d before ri din g.
Leakin g fuel is a fire hazar d.
EAU13213
FuelMake sure there is sufficient gasoline in
the tank.
WARNING
EWA10882
Gasoline an d gasoline vapors are
extremely flammab le. To avoid fires
an d explosions an d to re duce the
risk of injury when refuelin g, follow
these instructions.1. Before refueling, turn off the en- gine and be sure that no one is sit-
ting on the vehicle. Never refuel
while smoking, or while in the vi-
cinity of sparks, open flames, or
other sources of ignition such as
the pilot lights of water heaters
and clothes dryers.
2. Do not overfill the fuel tank. Stop filling when the fuel reaches the
bottom of the filler tube. Because
fuel expands when it heats up,
heat from the engine or the sun
can cause fuel to spill out of the
fuel tank.
1. Unlock.
1
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Instrument and control functions
3-9
3
3. Wipe up any spilled fuel immedi-ately. NOTICE: Immediately
wipe off spille d fuel with a clean,
d ry, soft cloth, since fuel may
d eteriorate painted surfaces or
plastic parts.
[ECA10072]
4. Be sure to securely close the fuel tank cap.
WARNING
EWA15152
Gasoline is poisonous an d can cau-
se injury or death. Han dle gasoline
with care. Never siphon gasoline by
mouth. If you shoul d swallow some
g asoline or inhale a lot of g asoline
vapor, or g et some gasoline in your
eyes, see your d octor immediately. If g
asoline spills on your skin, wash
with soap an d water. If g asoline
spills on your clothin g, chan ge your
clothes.
EAU76860
NOTICE
ECA11401
Use only unlea ded g asoline. The use
of lea ded g asoline will cause severe
d amag e to internal en gine parts,
such as the valves an d piston rin gs,
as well as to the exhaust system.
TIP This mark identifies the recom-
mended fuel for this vehicle as
specified by European regulation
(EN228).
 Check that gasoline nozzle has
the same identifier when fueling.Your Yamaha engine has been de-
signed to use regular unleaded gaso-
line with a research octane number of
95 or higher. If knocking (or pinging)
occurs, use a gasoline of a different
brand or premium unleaded fuel. Use
of unleaded fuel will extend spark plug
life and reduce maintenance costs.
1. Fuel tank filler tube
2. Maximum fuel level
1
2
Recommen ded fuel:
Regular unleaded gasoline (Gasohol
[E10] acceptable)
Fuel tank capacity:
14 L (3.7 US gal, 3.1 Imp.gal)
Fuel reserve amount: 2.2 L (0.58 US gal, 0.48 Imp.gal)
E10
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Instrument and control functions
3-13
3
EAU78340
Ig nition circuit cut-off systemThe ignition circuit cut-off system
(comprising the sidestand switch,
clutch switch and neutral switch) has
the following functions.
 It prevents starting when the
transmission is in gear and the
sidestand is up, but the clutch le-
ver is not pulled.
 It prevents starting when the
transmission is in gear and the
clutch lever is pulled, but the side-
stand is still down.
 It cuts the running engine when
the transmission is in gear and the
sidestand is moved down.
Periodically check the operation of the
ignition circuit cut-off system accord-
ing to the following procedure.UBT4E0E0.book Page 13 Thursday, November 17, 2016 10:55 AM

Instrument and control functions
3-14
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.
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.
Does the engine start?
The system is OK. The motorcycle can be ridden. The sidestand switch may not be working correctly.
The motorcycle should not be ridden
until
checked by a Yamaha dealer.
The clutch switch may not be working correctly.
The motorcycle should not be ridden until
checked by a Yamaha dealer.
YES NO YES NO YES NO
The neutral switch may not be working correctly.
The motorcycle should not be ridden until
checked by a Yamaha dealer. The vehicle must be placed on the center-
stand during this inspection.If a malfunction is noted, have a Yamaha
dealer check the system before riding.
WA R N I N G
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For your safety – pre-operation checks
4-1
4
EAU15599
Inspect your vehicle each time you use it to make sure the vehicle is in safe operating condition. Always follow the inspection
and maintenance procedures and schedules described in the Owner’s Manual.
WARNING
EWA11152
Failure to inspect or maintain the vehicle properly increases the possibility of an acci dent or equipment damag e.
Do not operate the vehicle if you fin d any pro blem. If a pro blem cannot be corrected b y the proce dures provi ded in
this manual, have the vehicle inspecte d b y a Yamaha dealer.Before using this vehicle, check the following points:
ITEM CHECKS PAGE
Fuel • Check fuel level in fuel tank.
• Refuel if necessary.
• Check fuel line for leakage. 3-8
En gine oil • Check oil level in engine.
• If necessary, add recommended oil to specified level.
• Check vehicle for oil leakage. 6-11
Front brake • Check 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 specified brake fluid to specified level.
• Check hydraulic system for leakage. 6-22, 6-22
Rear brake • Check operation.
• Check pedal free play.
• Adjust if necessary. 6-21, 6-22
Clutch • Check operation.
• Lubricate cable if necessary.
• Check lever free play.
• Adjust if necessary. 6-19
UBT4E0E0.book Page 1 Thursday, November 17, 2016 10:55 AM

Operation and important rid ing points
5-1
5
EAU15952
Read the Owner’s Manual carefully to
become familiar with all controls. If
there is a control or function you do not
understand, ask your Yamaha dealer.
WARNING
EWA10272
Failure to familiarize yourself with
the controls can lead to loss of con-
trol, which coul d cause an acci dent
or injury.
EAUM3150
TIPThis 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 “ ” and then to “ ”. Failing
to do so will prevent the engine from
starting even though the engine will
crank when pushing the start switch.
EAU78350
Startin g the en gineIn 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
sidestand up.
See page 3-13 for more informa-
tion.
1. Turn the key to “ ”. The engine trouble warning light
should come on for a few sec-
onds, then go off.NOTICE
ECA23970
If the warnin g li ght does not come
on initially when the key is turne d
to “ ”, or if the warnin g li ght re-
mains on, see pag e 3-2 for the warn-
in g lig ht circuit check.2. Shift the transmission into the
neutral position. The neutral indi-
cator light should come on. If not,
ask a Yamaha dealer to check the
electrical circuit.
UBT4E0E0.book Page 1 Thursday, November 17, 2016 10:55 AM