2017 YAMAHA YS125 ECU

Safety information
1-5
1operator and may limit control
ability, therefore, such accesso-
ries are not recommended.
 Use caution when adding electri-
cal accessories. If electrical ac-
cessories exceed the capacity of
the motorcycle’s electrical sys-
tem, an electric failure could re-
sult, which could cause a
dangerous loss of lights or engine
power.
Aftermarket Tires an d Rims
The tires and rims that came with your
motorcycle were designed to match
the performance capabilities and to
provide the best combination of han-
dling, braking, and comfort. Other
tires, rims, sizes, and combinations
may not be appropriate. Refer to page
6-17 for tire specifications and more in-
formation on replacing your tires.
Transportin g the Motorcycle
Be sure to observe following instruc-
tions before transporting the motorcy-
cle in another vehicle.  Remove all loose items from the
motorcycle. 
Check that the fuel cock (if
equipped) is in the “OFF” position
and that there are no fuel leaks.
 Point the front wheel straight
ahead on the trailer or in the truck
bed, and choke it in a rail to pre-
vent movement.
 Shift the transmission in gear (for
models with a manual transmis-
sion).
 Secure the motorcycle with tie-
downs or suitable straps that are
attached to solid parts of the mo-
torcycle, such as the frame or up-
per front fork triple clamp (and not,
for example, to rubber-mounted
handlebars or turn signals, or
parts that could break). Choose
the location for the straps carefully
so the straps will not rub against
painted surfaces during transport.
 The suspension should be com-
pressed somewhat by the tie-
downs, if possible, so that the mo-
torcycle will not bounce exces-
sively during transport.
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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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Periodic maintenance an d a djustment
6-9
6 2. Pull the front of the panel out, and
then slide the panel forward to re-
lease it in the rear.
To install the panel
1. Secure the rear of the panel, and then push the front of the panel in.
2. Install the screw. Panel B
To remove the panel
1. Slide the panel lock cover open,
insert the key into the lock, and
then turn it 1/4 turn clockwise.
2. Pull the front of the panel out with the key inserted in the lock, and
then slide the panel forward to re-
lease it in the rear. To install the panel
1. Secure the rear of the panel, and
then push the front of the panel in
with the key inserted in the lock.
2. While pushing the panel inward, turn the key counterclockwise to
the original position, remove it,
and then close the panel lock cov-
er.
1. Screw
1
1. Panel B
2. Panel lock cover
3. Unlock.
1
2
3
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Periodic maintenance an d a djustment
6-29
6
EAU23273
Checkin g the front forkThe condition and operation of the
front fork must be checked as follows
at the intervals specified in the periodic
maintenance and lubrication chart.
To check the con dition
Check the inner tubes for scratches,
damage and excessive oil leakage.
To check the operation 1. Place the vehicle on a level surfa- ce and hold it in an upright posi-
tion. WARNING! To avoi d injury,
securely support the vehicle so
there is no dan ger of it fallin g
over.
[EWA10752]
2. While applying the front brake, push down hard on the handle-
bars several times to check if the
front fork compresses and re-
bounds smoothly.
NOTICE
ECA10591
If any d amage is foun d or the front
fork does not operate smoothly,
have a Yamaha dealer check or re-
pair it.
EAU45512
Checkin g the steerin gWorn or loose steering bearings may
cause danger. Therefore, the operation
of the steering must be checked as fol-
lows at the intervals specified in the
periodic maintenance and lubrication
chart.
1. Place the vehicle on the center- stand. WARNING! To avoi d inju-
ry, securely support the vehicle
so there is no dan ger of it fallin g
over.
[EWA10752]
2. Hold the lower ends of the front fork legs and try to move them for-
ward and backward. If any free
play can be felt, have a Yamaha
dealer check or repair the steer-
ing.
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Periodic maintenance an d a djustment
6-34
6
4. Disconnect the headlight coupler,
then remove the headlight bulb
cover.
5. Unhook the headlight bulb holder, then remove the burnt-out bulb. 6. Place a new headlight bulb into
position, then secure it with the
bulb holder.
7. Install the headlight bulb cover, then connect the headlight cou-
pler.
8. Place the headlight unit in its orig- inal position, and then tighten the
headlight unit stay bolt to the
specified torque.
9. Install the bolt on each side.
10. Place the headlight unit side cov- ers in their original position, and
then install the screw on each
side.
11. Have a Yamaha dealer adjust the headlight beam if necessary.
EAU45226
Replacin g the auxiliary li ght
b ul b If the auxiliary light bulb burns out, re-
place it as follows.
1. Remove the headlight unit. (See page 6-33.)
2. Remove the auxiliary light bulb socket (together with the bulb) by
pulling it out.
3. Remove the burnt-out bulb by pulling it out.
4. Insert a new bulb into the socket.
5. Install the socket (together with the bulb) by pushing it in.
6. Install the headlight unit.
1. Headlight coupler
2. Headlight bulb holder
1. Headlight bulb holder
2. Headlight bulb
1 21
2
Ti
ghtenin g torque:
Headlight unit stay bolt: 7 N·m (0.7 kgf·m, 5.1 lb·ft)
1. Auxiliary light bulb
2. Auxiliary light bulb socket
1
2
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Periodic maintenance an d a djustment
6-36
6
3. Insert a new bulb into the socket,
push it in, and then turn it clock-
wise until it stops.
4. Install the lens by installing the screw. NOTICE: Do not over-
ti g hten the screw, otherwise the
lens may break.
[ECA11192] EAU78970
Replacin
g the license plate
lig ht bul b1. Remove the license plate light unit
by removing the nuts.
2. Remove the license plate light bulb socket (together with the
bulb) by pulling it out.
3. Remove the burnt-out bulb by pulling it out.
4. Insert a new bulb into the socket.
5. Install the socket (together with the bulb) by pushing it in.
6. Install the license plate light unit by installing the nuts.
EAU24361
Front wheel
EAUW3361
To remove the front wheel
WARNING
EWA10822
To avoi d injury, securely support the
vehicle so there is no dan ger of it
fallin g over.1. Take the vehicle off the center-
stand so that the front wheel is on
the ground, and then put the side-
stand down.
2. Loosen the front wheel axle nut.
1. Turn signal light bulb
1
1. License plate light unit
2. License plate light bulb
3. License plate light bulb socket
4. Nut
1
32
4
4
1. Axle nut
1
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Periodic maintenance an d a djustment
6-37
6 3. Place the vehicle on the center-
stand, and then remove the axle
nut.
4. Pull the wheel axle out, and then remove the wheel. NOTICE: Do
not apply the b rake after the
wheel an d b rake disc have b een
remove d, otherwise the brake
pa ds will be forced shut.
[ECA11073]
To install the front wheel
1. Lift the wheel up between the fork legs.TIPMake sure that there is enough space
between the brake pads before insert-
ing the brake disc into the caliper.
2. Insert the wheel axle, and then in-stall the axle nut.
3. Take the vehicle off the center- stand so that the front wheel is on
the ground, and then put the side-
stand down.
4. Tighten the axle nut to the speci- fied torque.
5. Push down hard on the handlebar several times to check for proper
fork operation.
EAU25081
Rear wheel
EAU78751
To remove the rear wheel
WARNING
EWA10822
To avoi d injury, securely support the
vehicle so there is no dan ger of it
fallin g over.1. Take the motorcycle off the cen-
terstand so that the rear wheel is
on the ground, and then put the
sidestand down.
2. Loosen the axle nut.
3. Disconnect the brake torque rod from the brake shoe plate by re-
moving the nut and the bolt.
1. Wheel axle
1
Tightenin g torque:
Axle nut: 59 N·m (5.9 kgf·m, 43 lb·ft)
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Consumer information
9-2
9
The model label is affixed to the frame
behind panel A. (See page 6-8.) Re-
cord the information on this label in the
space provided. This information will
be needed when ordering spare parts
from a Yamaha dealer.
EAU69910
Dia
gnostic connectorThe diagnostic connector is located as
shown.
EAU74701
Vehicle data recor din gThis model’s ECU stores certain vehi-
cle data to assist in the diagnosis of
malfunctions and for research and de-
velopment purposes. This data will be
uploaded only when a special Yamaha
diagnostic tool is attached to the vehi-
cle, such as when maintenance checks
or service procedures are performed.
Although the sensors and recorded
data will vary by model, the main data
points are:
 Vehicle status and engine perfor-
mance data
 Fuel-injection and emission-relat-
ed data
Yamaha will not disclose this data to a
third party except:  With the consent of the vehicle
owner
 Where obligated by law
 For use by Yamaha in litigation
 For general Yamaha-conducted
research purposes when the data
is not related to an individual vehi-
cle nor owner
1. Diagnostic connector
1
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