2007 YAMAHA CYGNUS 125 check engine

PERIODIC MAINTENANCE AND MINOR REPAIR
6-14
2
3
4
5
67
8
9

EAU21382
Checking the throttle cable
free play
The throttle cable free play should mea-
sure 3.0–5.0 mm (0.12–0.20 in) at the
throttle grip. Periodically check the
throttle cable free play and, if neces-
sary, have a Yamaha dealer adjust it.
EAU21401
Valve clearance
The valve clearance changes with use,
resulting in improper air-fuel mixture
and/or engine noise. To prevent this
from occurring, the valve clearance
must be adjusted by a Yamaha dealer
at the intervals specified in the periodic
maintenance and lubrication chart.
EAUT2140
Tires
To maximize the performance, durabil-
ity, and safe operation of your vehicle,
note the following points regarding the
specified tires.
Tire air pressure
The tire air pressure should be checked
and, if necessary, adjusted before each
ride.
WARNING

EWA10500

The tire air pressure must be
checked and adjusted on cold
tires (i.e., when the temperature
of the tires equals the ambient
temperature).

The tire air pressure must be ad-
justed in accordance with the
riding speed and with the total
weight of rider, passenger, car-
go, and accessories approved
for this model.
1. Throttle cable free play
ZAUM00**
1

PERIODIC MAINTENANCE AND MINOR REPAIR
6-19
1
2
3
4
5
6
7
8
9
check the cause.

EAU22720
Changing the brake fluid
Have a Yamaha dealer change the
brake fluid at the intervals specified in
the NOTE after the periodic mainte-
nance and lubrication chart. In addition,
have the oil seals of the brake master
cylinder and caliper as well as the
brake hose replaced at the intervals
listed below or whenever they are dam-
aged or leaking.

Oil seals: Replace every two
years.

Brake hose: Replace every four
years.
EAU23100
Checking and lubricating the
cables
The operation of all control cables and
the condition of the cables should be
checked before each ride, and the ca-
bles and cable ends should be lubricat-
ed if necessary. If a cable is damaged
or does not move smoothly, have a
Yamaha dealer check or replace it.
WARNING

EWA10720
Damage to the outer sheath may in-
terfere with proper cable operation
and will cause the inner cable to
rust. Replace a damaged cable as
soon as possible to prevent unsafe
conditions.
Recommended lubricant:
Engine oil

PERIODIC MAINTENANCE AND MINOR REPAIR
6-21
1
2
3
4
5
6
7
8
9

EAU23271
Checking the front fork
The condition and operation of the front
fork must be checked as follows at the
intervals specified in the periodic main-
tenance and lubrication chart.
To check the condition
WARNING

EWA10750
Securely support the vehicle so that
there is no danger of it falling over.
Check the inner tubes for scratches,
damage and excessive oil leakage.
To check the operation
1. Place the vehicle on a level sur-
face and hold it in an upright posi-
tion.
2. While applying the front brake,
push down hard on the handlebars
several times to check if the front
fork compresses and rebounds
smoothly.
CAUTION:

ECA10590
If any damage is found or the front
fork does not operate smoothly,
have a Yamaha dealer check or re-
pair it.
EAU23280
Checking the steering
Worn 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 pe-
riodic maintenance and lubrication
chart.
1. Place a stand under the engine to
raise the front wheel off the
ground.
WARNING

EWA10750
Securely support the vehicle so that
there is no danger of it falling over.
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 steering.
ZAUM00**

PERIODIC MAINTENANCE AND MINOR REPAIR
6-29
1
2
3
4
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6
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9

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.

SCOOTER CARE AND STORAGE
7-4
1
2
3
4
5
6
7
8
9
fuel from deteriorating.
3. Perform the following steps to pro-
tect the cylinder, piston rings, etc.
from corrosion.
a. Remove the spark plug cap
and spark plug.
b. Pour a teaspoonful of engine oil
into the spark plug bore.
c. Install the spark plug cap onto
the spark plug, and then place
the spark plug on the cylinder
head so that the electrodes are
grounded. (This will limit spark-
ing during the next step.)
d. Turn the engine over several
times with the starter. (This will
coat the cylinder wall with oil.)
e. Remove the spark plug cap
from the spark plug, and then
install the spark plug and the
spark plug cap.
WARNING

EWA10950
To prevent damage or injury from
sparking, make sure to ground the
spark plug electrodes while turning
the engine over.
4. Lubricate all control cables and thepivoting points of all levers and
pedals as well as of the sidestand/
centerstand.
5. Check and, if necessary, correct
the tire air pressure, and then lift
the scooter so that both of its
wheels are off the ground. Alterna-
tively, turn the wheels a little every
month in order to prevent the tires
from becoming degraded in one
spot.
6. Cover the muffler outlet with a
plastic bag to prevent moisture
from entering it.
7. Remove the battery and fully
charge it. Store it in a cool, dry
place and charge it once a month.
Do not store the battery in an ex-
cessively cold or warm place [less
than 0 °C (30 °F) or more than 30
°C (90 °F)]. For more information
on storing the battery, see page
6-22.
NOTE:

Make any necessary repairs before
storing the scooter.

INDEX
A
Acceleration and deceleration................... 5-2
Air filter and V-belt case air filter
elements ............................................... 6-12
Auxiliary light bulb, replacing .................. 6-27
B
Battery..................................................... 6-22
Brake fluid, changing .............................. 6-19
Brake fluid level, checking ...................... 6-18
Brake lever, front....................................... 3-6
Brake lever, rear ....................................... 3-7
Brake levers, lubricating.......................... 6-20
Brake pads and shoes, checking ............ 6-17
Braking ...................................................... 5-2
C
Cables, checking and lubricating ............ 6-19
Care .......................................................... 7-1
Catalytic converter .................................... 3-9
Centerstand and sidestand, checking and
lubricating ............................................. 6-20
D
Dimmer switch .......................................... 3-6
E
Engine break-in ......................................... 5-3
Engine oil and oil strainer.......................... 6-9
Engine trouble warning light...................... 3-3
F
Final transmission oil .............................. 6-11
Front fork, checking ................................ 6-21
Fuel ........................................................... 3-8
Fuel consumption, tips for reducing .......... 5-3
Fuel tank cap ............................................ 3-7
Fuses, replacing...................................... 6-24
H
Handlebar switches ...................................3-5
Headlight bulb, replacing .........................6-25
High beam indicator light ...........................3-2
Horn switch ................................................3-6
I
Identification numbers................................9-1
Indicator and warning lights .......................3-2
K
Keyhole cover ............................................3-2
Key identification number ..........................9-1
Kickstarter ..................................................3-9
M
Main switch ................................................3-1
Matte color, caution ...................................7-1
Model label ................................................9-2
Multi-function display .................................3-3
P
Panels, removing and installing .................6-6
Parking.......................................................5-4
Part locations .............................................2-1
Periodic maintenance and lubrication
chart ........................................................6-3
Pre-operation check list .............................4-2
R
Rear brake lever free play, adjusting .......6-16
S
Safe-riding points .......................................1-4
Safety information ......................................1-1
Seat ...........................................................3-9
Sidestand .................................................3-11
Sidestand switch operation check ...........3-12
Spark plug, checking .................................6-7
Specifications.............................................8-1Speedometer ............................................. 3-3
Starting off ................................................. 5-2
Starting the engine .................................... 5-1
Start switch ................................................ 3-6
Steering, checking ................................... 6-21
Storage ...................................................... 7-3
Storage compartments ............................ 3-10
T
Tail/brake light bulb or rear turn signal
light bulb, replacing ............................... 6-27
Throttle cable free play, checking............ 6-14
Throttle grip and cable, checking and
lubricating .............................................. 6-20
Tires ........................................................ 6-14
Tool kit ....................................................... 6-1
Troubleshooting....................................... 6-28
Troubleshooting chart.............................. 6-29
Turn signal indicator light .......................... 3-2
Turn signal light bulb (front), replacing .... 6-26
Turn signal switch...................................... 3-6
V
Valve clearance ....................................... 6-14
Vehicle identification number .................... 9-1
W
Wheel bearings, checking ....................... 6-22
Wheels .................................................... 6-16