2017 YAMAHA YS125 Owners Manual

Instrument and control functions
3-10
3
Gasohol
There are two types of gasohol: gaso-
hol containing ethanol and that con-
taining methanol. Gasohol containing
ethanol can be used if the ethanol con-
tent does not exceed 10% (E10). Gas-
ohol containing methanol is not
recommended by Yamaha because it
can cause damage to the fuel system
or vehicle performance problems.
EAU13447
Catalytic converters This vehicle is equipped with catalytic
converters in the exhaust system.
WARNING
EWA10863
The exhaust system is hot after op-
eration. To prevent a fire hazar
d or
b urns:
 Do not park the vehicle near
possi ble fire hazar ds such as
g rass or other materials that
easily burn.
 Park the vehicle in a place
where pe destrians or chil dren
are not likely to touch the hot
exhaust system.
 Make sure that the exhaust sys-
tem has cooled down before
d oin g any maintenance work.
 Do not allow the en gine to id le
more than a few minutes. Lon g
i d lin g can cause a buil d-up of
heat.
NOTICE
ECA10702
Use only unlea ded g asoline. The use
of lea ded g asoline will cause unre-
paira ble damag e to the catalytic
converter.
UBT4E0E0.book Page 10 Thursday, November 17, 2016 10:55 AM

Instrument and control functions
3-11
3
EAU78851
SeatTo remove the seat
1. Remove panels A and B. (See page 6-8.)
2. Remove the bolts. 3. Lift the front of the seat and pull it
forward.
To install the seat 1. Insert the projection on the rear of the seat into the seat holder as
shown.
2. Place the seat in the original posi- tion, and then tighten the bolts.
3. Install the panels.
TIPMake sure that the seat is properly se-
cured before riding.
EAU68420
A djustin g the shock a bsorb er
assem blies
WARNING
EWA10211
Always a djust both shock a bsor ber
assem blies equally, otherwise poor
han dlin g an d loss of sta bility may re-
sult.Each shock absorber assembly is
equipped with a spring preload adjust-
ing ring.NOTICE
ECA10102
To avoi d d amag ing the mechanism,
d o not attempt to turn b eyond the
maximum or minimum settin gs.Adjust the spring preload as follows.
To increase the spring preload and
thereby harden the suspension, turn
the adjusting ring on each shock ab-
sorber assembly in direction (a). To de-
crease the spring preload and thereby
soften the suspension, turn the adjust-
ing ring on each shock absorber as-
sembly in direction (b).
1. Bolt
1. Bolt
1
1
1. Projection
2. Seat holder
1
2
UBT4E0E0.book Page 11 Thursday, November 17, 2016 10:55 AM

Instrument and control functions
3-12
3

Align the appropriate notch in the
adjusting ring with the position in-
dicator on the shock absorber.
 Use the screwdriver included in
the owner’s tool kit to make this
adjustment.
EAU15306
Sidestan dThe sidestand is located on the left
side of the frame. Raise the sidestand
or lower it with your foot while holding
the vehicle upright.TIPThe built-in sidestand switch is part of
the ignition circuit cut-off system,
which cuts the ignition in certain situa-
tions. (See the following section for an
explanation of the ignition circuit cut-
off system.)
WARNING
EWA10242
The vehicle must not b e ridden with
the si destan d d own, or if the si de-
stan d cannot b e properly move d up
(or does not stay up), otherwise the
si destan d coul d contact the groun d
an d d istract the operator, resultin g
in a possib le loss of control.
Yamaha’s ig nition circuit cut-off
system has been desi gne d to assist
the operator in fulfillin g the respon-
si bility of raisin g the si destan d b e-
fore startin g off. Therefore, check this system re
gularly an d have a
Yamaha dealer repair it if it does not
function properly.
1. Spring preload adjusting ring
2. Position indicator
3. ScrewdriverSprin g preloa d settin g:
Minimum (soft):
1
Standard: 2
Maximum (hard): 5
2
13(a)
(b)
UBT4E0E0.book Page 12 Thursday, November 17, 2016 10:55 AM

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
UBT4E0E0.book Page 14 Thursday, November 17, 2016 10:55 AM

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

For your safety – pre-operation checks
4-2
4
Throttle grip • Make sure that operation is smooth.
• Check throttle grip free play.
• If necessary, have Yamaha dealer adjust throttle grip free play and lubricate ca-
ble and grip housing. 6-16, 6-26
Control ca bles • Make sure that operation is smooth.
• Lubricate if necessary.
6-26
Drive chain • Check chain slack.
• Adjust if necessary.
• Check chain condition.
• Lubricate if necessary. 6-24, 6-25
Wheels an d tires • Check for damage.
• Check tire condition and tread depth.
• Check air pressure.
• Correct if necessary. 6-17, 6-19
Brake an d shift pe dals • Make sure that operation is smooth.
• Lubricate pedal pivoting points if necessary.
6-26
Brake an d clutch levers • Make sure that operation is smooth.
• Lubricate lever pivoting points if necessary. 6-27
Centerstan d, si destan d • Make sure that operation is smooth.
• Lubricate pivots if necessary. 6-28
Chassis fasteners • Make sure that all nuts, bolts and screws are properly tightened.
• Tighten if necessary.
—
Instruments, li ghts, si gnals
an d switches • Check operation.
• Correct if necessary.
—
Si destan d switch • Check operation of ignition circuit cut-off system.
• If system is not working correctly, have Yamaha dealer check vehicle. 3-12
ITEM CHECKS PAGE
UBT4E0E0.book Page 2 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