2007 YAMAHA CYGNUS 125 Owners Manual

PERIODIC MAINTENANCE AND MINOR REPAIR
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EAU23290
Checking the wheel bearings
The front and rear wheel bearings must
be checked at the intervals specified in
the periodic maintenance and lubrica-
tion chart. If there is play in the wheel
hub or if the wheel does not turn
smoothly, have a Yamaha dealer check
the wheel bearings.
EAUT1853
Battery
This model is equipped with a
sealed-type (MF) battery, which does
not require any maintenance. There is
no need to check the electrolyte or to
add distilled water.
NOTE:

The battery is located behind panel D.
(See page 6-6.)
WARNING

EWA10760

Electrolyte is poisonous and
dangerous since it contains sul-
furic acid, which causes severe
burns. Avoid any contact with
skin, eyes or clothing and al-
ZAUM00**

1. Battery
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1

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9ways shield your eyes when
working near batteries. In case
of contact, administer the fol-
lowing FIRST AID.


EXTERNAL: Flush with plenty
of water.

INTERNAL: Drink large quan-
tities of water or milk and im-
mediately call a physician.

EYES: Flush with water for 15
minutes and seek prompt
medical attention.

Batteries produce explosive hy-
drogen gas. Therefore, keep
sparks, flames, cigarettes, etc.,
away from the battery and pro-
vide sufficient ventilation when
charging it in an enclosed
space.

KEEP THIS AND ALL BATTER-
IES OUT OF THE REACH OF
CHILDREN.
To charge the battery
Have a Yamaha dealer charge the bat-
tery as soon as possible if it seems to
have discharged. Keep in mind that the
battery tends to discharge more quicklyif the vehicle is equipped with optional
electrical accessories.
To store the battery
1. If the vehicle will not be used for
more than one month, remove the
battery, fully charge it, and then
place it in a cool, dry place.
2. If the battery will be stored for more
than two months, check it at least
once a month and fully charge it if
necessary.
3. Fully charge the battery before in-
stallation.
4. Before installation, make sure that
the battery leads are properly con-
nected to the battery terminals.
CAUTION:

ECAT1051

Always keep the battery
charged. Storing a discharged
battery can cause permanent
battery damage.

To charge a sealed-type (MF)
battery, a special (constant-volt-
age) battery charger is required.
Using a conventional battery
charger will damage the battery.
If you do not have access to asealed-type (MF) battery charg-
er, have a Yamaha dealer
charge your battery.

After installing the battery, be
sure to turn the main switch
from “ON” to “OFF” three times
in 3 seconds intervals to initial-
ize the idle speed control sys-
tem.

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EAUT1914
Replacing the fuses
The main fuse box is located above the
battery.
The fuse box, which contains the fuses
for the individual circuits, is located in
the storage compartment. (See
page 3-10.)If a fuse is blown, replace it as follows.
1. Turn the key to “OFF” and turn off
the electrical circuit in question.
2. Remove the blown fuse, and then
install a new fuse of the specified
amperage.
CAUTION:

ECAT1061

Do not use a fuse of a higher
amperage rating than recom-
mended to avoid causing exten-
sive damage to the electrical
system and possibly a fire.

After removing and installing
the main fuse, be sure to turn
the main switch from “ON” to
“OFF” three times in 3 seconds
intervals to initialize the idle
speed control system.
3. Turn the key to “ON” and turn on
the electrical circuit in question to
check if the device operates.
1. Main fuse
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1. Lid
2. Backup fuse
3. Ignition fuse
4. Signaling system fuse
5. Taillight fuse
6. Headlight fuse
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Specified fuses:
Main fuse:
20.0 A
Headlight fuse:
15.0 A
Signaling system fuse:
15.0 A
Ignition fuse:
7.5 A
Backup fuse:
7.5 A
Taillight fuse:
7.5 A

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4. If the fuse immediately blows
again, have a Yamaha dealer
check the electrical system.

EAUT2130
Replacing the headlight bulb
This model is equipped with a quartz
bulb headlight. If the headlight bulb
burns out, replace it as follows.
1. Place the vehicle on the center-
stand.
2. Remove panel B. (See page 6-6.)
3. Disconnect the headlight coupler,
and then remove the bulb cover.
4. Unhook the headlight bulb holder,
and then remove the defective
bulb.
WARNING

EWA10790
Headlight bulbs get very hot. There-
fore, keep flammable products away
from a lit headlight bulb, and do not
touch the bulb until it has cooled
down.
5. Place a new headlight bulb into po-
sition, and then secure it with the
bulb holder.
CAUTION:

ECA10660
Do not touch the glass part of the
headlight bulb to keep it free from
oil, otherwise the transparency of
the glass, the luminosity of the bulb,
and the bulb life will be adversely af-
1. Bulb cover
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1. Headlight bulb holder
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9 fected. Thoroughly clean off any dirt
and fingerprints on the headlight
bulb using a cloth moistened with al-

cohol or thinner.
6. Install the headlight bulb cover,
and then connect the coupler.
7. Install the panel.
8. Have a Yamaha dealer adjust the
headlight beam if necessary.
EAUT1891
Replacing a front turn signal
light bulb
CAUTION:

ECA10670
It is advisable to have a Yamaha
dealer perform this job.
1. Place the scooter on the center-
stand.
2. Remove panel A. (See page 6-6.)
3. Remove the socket (together with
the bulb) by turning it counter-
clockwise.
4. Remove the defective bulb by
pushing it in and turning it counter-
clockwise.5. Insert a new bulb into the socket,
push it in, and then turn it clock-
wise until it stops.
6. Install the socket (together with the
bulb) by turning it clockwise.
7. Install the panel.
1. Turn signal light bulb
2. Socket
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EAUT1922
Replacing the tail/brake light
bulb or a rear turn signal light
bulb
Tail/brake light bulb
1. Remove the tail/brake light lens by
removing the screws.
2. Remove the defective bulb by
pushing it in and turning it counter-
clockwise.
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 thescrews.
Rear turn signal light bulb
1. Remove the tail/brake light lens by
removing the screws.
2. Remove the turn signal light lens
by removing the screws.
3. Remove the defective bulb by
pushing it in and turning it counter-
clockwise.
4. Insert a new bulb into the socket,
push it in, and then turn it clock-
wise until it stops.
5. Install the turn signal light lens by
installing the screws.
6. Install the tail/brake light lens by in-
stalling the screws.
CAUTION:

ECA10680
Do not overtighten the screws, oth-
erwise the lens may break.
EAUT1962
Replacing an auxiliary light
bulb
This model is equipped with two auxil-
iary lights. If an auxiliary light bulb burns
out, replace it as follows.
1. Remove panel B. (See page 6-6.)
2. Remove the auxiliary light socket
(together with the bulb) by turning
it counterclockwise.
3. Remove the defective bulb by pull-
ing it out.
4. Insert a new bulb into the socket.
5. Install the auxiliary light socket (to-
gether with the bulb) by turning it
clockwise.
1. Tail/brake light lens
2. Turn signal light lens
3. Rear turn signal light bulb
4. Tail/brake light bulb
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1. Auxiliary light bulb
2. Socket
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6. Install the panel.

EAU25860
Troubleshooting
Although Yamaha scooters receive a
thorough inspection before shipment
from the factory, trouble may occur dur-
ing operation. Any problem in the fuel,
compression, or ignition systems, for
example, can cause poor starting and
loss of power.
The following troubleshooting chart
represents a quick and easy procedure
for checking these vital systems your-
self. However, should your scooter re-
quire any repair, take it to a Yamaha
dealer, whose skilled technicians have
the necessary tools, experience, and
know-how to service the scooter prop-
erly.
Use only genuine Yamaha replace-
ment parts. Imitation parts may look like
Yamaha parts, but they are often inferi-
or, have a shorter service life and can
lead to expensive repair bills.

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EAUT1980
Troubleshooting chart
WARNING

EWA10840
Keep away open flames and do not smoke while checking or working on the fuel system.
Check the fuel level in
the fuel tank.1. Fuel
There is enough fuel.
There is no fuel.
Check the compression.
Supply fuel.
The engine does not start.
Check the compression.
Operate the electric starter.2. Compression
There is compression.
There is no compression.
Check the ignition.
Have a Yamaha dealer
check the vehicle.
Remove the spark plug
and check the electrodes.3. Ignition
Wipe off with a dry cloth and correct the
spark plug gap, or replace the spark plug.
Have a Yamaha dealer check the vehicle.
The engine does not start.
Have a Yamaha dealer
check the vehicle.
The engine does not start.
Check the battery.
Operate the electric starter.4. Battery
The engine turns over
quickly.
The engine turns over
slowly.
The battery is good.Check the battery lead connections,
and charge the battery if necessary.
DryWet
Operate the electric starter.