engine YAMAHA YS125 2017 User Guide

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
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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.
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Operation and important ri din g points
5-2
5
3. Start the engine by pushing the
start switch.
If the engine fails to start when us-
ing the start switch, release it, wait
a few seconds, and then try again.
Each starting attempt should be
as short as possible to preserve
the battery. Do not crank the en-
gine more than 10 seconds on any
one attempt.
NOTICE
ECA11043
For maximum en gine life, never ac-
celerate har d when the en gine is
col d!
EAU16673
Shiftin gShifting gears lets you control the
amount of engine power available for
starting off, accelerating, climbing hills,
etc.
The gear positions are shown in the il-
lustration.TIPTo shift the transmission into the neu-
tral position, press the shift pedal down
repeatedly until it reaches the end of its
travel, and then slightly raise it.
NOTICE
ECA10261
Even with the transmission in
the neutral position, d o not
coast for lon g period s of time
with the en gine off, an d d o not
tow the motorcycle for lon g d is-
tances. The transmission is
properly lu bricated only when
the en gine is runnin g. Ina de-
quate lu brication may d amage
the transmission.
 Always use the clutch while
chan gin g g ears to avoi d d am-
a g in g the en gine, transmission,
an d d rive train, which are not
d esi gne d to withstan d the
shock of force d shiftin g.
1. Shift pedal
2. Neutral position
1
N
2 3
4
5
1
2
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Operation and important rid ing points
5-3
5
EAU16811
Tips for re ducin g fuel con-
sumptionFuel consumption depends largely on
your riding style. Consider the follow-
ing tips to reduce fuel consumption:
 Shift up swiftly, and avoid high en-
gine speeds during acceleration.
 Do not rev the engine while shift-
ing down, and avoid high engine
speeds with no load on the en-
gine.
 Turn the engine off instead of let-
ting it idle for an extended length
of time (e.g., in traffic jams, at traf-
fic lights or at railroad crossings).
EAU16831
Engine break-inThere is never a more important period
in the life of your engine than the period
between 0 and 1000 km (600 mi). For
this reason, you should read the fol-
lowing material carefully.
Since the engine is brand new, do not
put an excessive load on it for the first
1000 km (600 mi). The various parts in
the engine wear and polish themselves
to the correct operating clearances.
During this period, prolonged full-throt-
tle operation or any condition that
might result in engine overheating
must be avoided.
EAU16883
0–150 km (0–90 mi)
Avoid prolonged operation above 4500
r/min.
After every hour of operation, stop the
engine, and then let it cool for five to
ten minutes.
Vary the engine speed from time to
time. Do not operate the engine at one
set throttle position. 150–500 km (90–300 mi)
Avoid prolonged operation above 5400
r/min.
Rev the engine freely through the
gears, but do not use full throttle at any
time.
500–1000 km (300–600 mi)
Avoid prolonged full-throttle operation.
Avoid prolonged operation above 7000
r/min.
NOTICE: After 1000 km (600
mi) of operation, the en gine oil must
b e chan ged an d the oil filter car-
tri dge or element replace d.
[ECA10303]
1000 km (600 mi) an d b eyon d
The vehicle can now be operated nor-
mally.NOTICE
ECA10311
 Keep the en gine spee d out of
the tachometer red zone.
 If any en gine trou ble shoul d oc-
cur during the en gine break-in
period , imme diately have a
Yamaha dealer check the vehi-
cle.
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Operation and important ri din g points
5-4
5
EAU17214
Parkin gWhen parking, stop the engine, and
then remove the key from the main
switch.
WARNING
EWA10312
Since the en gine an d exhaust
system can b ecome very hot,
park in a place where pe destri-
ans or chil dren are not likely to
touch them an d b e burne d.
 Do not park on a slope or on soft
groun d, otherwise the vehicle
may overturn, increasin g the
risk of a fuel leak an d fire.
 Do not park near grass or other
flamma ble materials which
mi ght catch fire.
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Periodic maintenance an d a djustment
6-1
6
EAU17246
Periodic inspection, adjustment, and
lubrication will keep your vehicle in the
safest and most efficient condition
possible. Safety is an obligation of the
vehicle owner/operator. The most im-
portant points of vehicle inspection,
adjustment, and lubrication are ex-
plained on the following pages.
The intervals given in the periodic
maintenance charts should be simply
considered as a general guide under
normal riding conditions. However, de-
pending on the weather, terrain, geo-
graphical location, and individual use,
the maintenance intervals may need to
be shortened.
WARNING
EWA10322
Failure to properly maintain the vehi-
cle or performin g maintenance ac-
tivities incorrectly may increase
your risk of injury or death durin g
service or while usin g the vehicle. If
you are not familiar with vehicle ser-
vice, have a Yamaha d ealer perform
service.
WARNING
EWA15123
Turn off the en gine when performin g
maintenance unless otherwise
specified .
 A runnin g en gine has movin g
parts that can catch on body
parts or clothin g an d electrical
parts that can cause shocks or
fires.
 Runnin g the en gine while ser-
vicin g can lead to eye injury,
b urns, fire, or car bon monoxi de
poisonin g – possi bly lea din g to
d eath. See pag e 1-3 for more in-
formation a bout car bon monox-
i d e.
WARNING
EWA15461
Brake discs, calipers, drums, and
linin gs can b ecome very hot d uring
use. To avoi d possi ble burns, let
b rake components cool before
touchin g them.
EAU17303
Emission controls not only function to
ensure cleaner air, but are also vital to
proper engine operation and maximum
performance. In the following periodic
maintenance charts, the services relat-
ed to emissions control are grouped
separately. These services require
specialized data, knowledge, and
equipment. Maintenance, replace-
ment, or repair of the emission control
devices and systems may be per-
formed by any repair establishment or
individual that is certified (if applicable).
Yamaha dealers are trained and equipped to perform these particular
services.
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