check engine YAMAHA CYGNUS 125 2007 User Guide

PERIODIC MAINTENANCE AND MINOR REPAIR
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To install the panel
Place the panel in the original position,
and then install the screws.
Panel D
To remove the panel1. Open the seat. (See page 3-9.)2. Remove the quick fasteners by
pushing in the center pin, and then
take the panel off.
To install the panel
Place the panel in the original position,
and then install quick fasteners.

EAUT1830
Checking the spark plug
The spark plug is an important engine
component, which is easy to check.
Since heat and deposits will cause any
spark plug to slowly erode, the spark
plug should be removed and checked
in accordance with the periodic mainte-
nance and lubrication chart. In addition,
the condition of the spark plug can re-
veal the condition of the engine.
To remove the spark plug
1. Remove panel C. (See page 6-6.)
2. Remove the spark plug cap.
3. Remove the spark plug as shown,
with the spark plug wrench includ-
ed in the owner’s tool kit.
1. Panel C
2. Screw
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1. Panel D
2. Screw
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1. Spark plug wrench
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1. Check that the porcelain insulator
around the center electrode of the
spark plug is a medium-to-light tan
(the ideal color when the vehicle is
ridden normally).
NOTE:

If the spark plug shows a distinctly dif-
ferent color, the engine could be defec-
tive. Do not attempt to diagnose such
problems yourself. Instead, have a
Yamaha dealer check the vehicle.
2. Check the spark plug for electrode
erosion and excessive carbon or
other deposits, and replace it if
necessary.
To install the spark plug
1. Measure the spark plug gap with a
wire thickness gauge and, if nec-
essary, adjust the gap to specifica-
tion.2. Clean the surface of the spark plug
gasket and its mating surface, and
then wipe off any grime from the
spark plug threads.
3. Install the spark plug with the
spark plug wrench, and then tight-
en it to the specified torque.
NOTE:

If a torque wrench is not available when
installing a spark plug, a good estimateof the correct torque is 1/4–1/2 turn
past finger tight. However, the spark
plug should be tightened to the speci-
fied torque as soon as possible.
4. Install the spark plug cap.
5. Install the panel.
Specified spark plug:
NGK/CR7E
1. Spark plug gap
Spark plug gap:
0.7–0.8 mm (0.028–0.031 in)
Tightening torque:
Spark plug:
13 Nm (1.3 m·kgf, 9.4 ft·lbf)
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EAUT1351
Engine oil and oil strainer
The engine oil level should be checked
before each ride. In addition, the oil
must be changed and the oil strainer
cleaned at the intervals specified in the
periodic maintenance and lubrication
chart. The engine oil must also be
changed at the initial 1000 km (600 mi)
and when the oil change indicator flash-
es. The oil change tripmeter must be
reset after the initial 1000 km (600 mi).
(See page 3-2 for reset procedures.)
To check the engine oil level
1. Place the vehicle on the center-
stand.
NOTE:

Make sure that the vehicle is positioned
straight up when checking the oil level.
A slight tilt to the side can result in a
false reading.
2. Start the engine, warm it up for
several minutes, and then turn it
off.
3. Wait a few minutes until the oil set-
tles, remove the oil filler cap, wipe
the dipstick clean, insert it backinto the oil filler hole (without
screwing it in), and then remove it
again to check the oil level.
NOTE:

The engine oil should be between the
minimum and maximum level marks.
4. If the engine oil is below the mini-
mum level mark, add sufficient oil
of the recommended type to raise
it to the correct level.
5. Insert the dipstick into the oil filler
hole, and then tighten the oil filler
cap.
To change the engine oil and clean
the oil strainer
1. Start the engine, warm it up for
several minutes, and then turn it
off.
2. Place an oil pan under the engine
to collect the used oil.
3. Remove the engine oil filler cap
and drain bolts to drain the oil from
the crankcase.
CAUTION:

ECA10410
When removing the engine oil drain
bolt, the O-ring, spring, and oil
strainer will fall out. Take care not to
lose these parts.
1. Maximum level mark
2. Minimum level mark
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1. Oil filler cap
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4. Clean the oil strainer with solvent,
and then check it for damage and
replace it if necessary.
5. Check the O-ring for damage and
replace it if necessary.
6. Install the oil strainer, spring,O-ring and engine oil drain bolts,
and then tighten the drain bolts to
the specified torque.
NOTE:

Make sure that the O-ring is properly
seated.
7. Add the specified amount of the
recommended engine oil, and then
install and tighten the engine oil fill-
er cap.
CAUTION:

ECA11670

Do not use oils with a diesel
specification of “CD” or oils of a
higher quality than specified. In
addition, do not use oils labeled
“ENERGY CONSERVING II” orhigher.

Be sure no foreign material en-
ters the crankcase.
8. Start the engine, and then let it idle
for several minutes while checking
it for oil leakage. If oil is leaking, im-
mediately turn the engine off and
check for the cause.
9. Turn the engine off, and then
check the oil level and correct it if
necessary.
10. Reset the oil change tripmeter.
(See page 3-2 for reset proce-
dures.)
NOTE:

If the engine oil is changed before the
oil change indicator flashes (i.e. before
the periodic oil change interval has
been reached), the oil change tripmeter
must be reset after the oil change for
the next periodic oil change to be indi-
cated at the correct time.
1. Engine oil drain bolt A
1. Engine oil drain bolt B
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Tightening torque:
Engine oil drain bolt A:
20 Nm (2.0 m·kgf, 14.5 ft·lbf)
Engine oil drain bolt B:
20 Nm (2.0 m·kgf, 14.5 ft·lbf)
Recommended engine oil:
See page 8-1.
Oil change quantity:
0.90 L (0.95 US qt) (0.79 Imp.qt)

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EAU20061
Final transmission oil
The final transmission case must be
checked for oil leakage before each
ride. If any leakage is found, have a
Yamaha dealer check and repair the
scooter. In addition, the final transmis-
sion oil must be changed as follows at
the intervals specified in the periodic
maintenance and lubrication chart.
1. Start the engine, warm up the final
transmission oil by riding the
scooter for several minutes, and
then stop the engine.
2. Place the scooter on the center-
stand.
3. Place an oil pan under the final
transmission case to collect the
used oil.
4. Remove the oil filler cap and drain
bolt to drain the oil from the final
transmission case.5. Install the final transmission oil
drain bolt, and then tighten it to the
specified torque.6. Add the specified amount of the
recommended final transmission
oil, and then install and tighten the
oil filler cap.
WARNING

EWA11310

Make sure that no foreign mate-
rial enters the final transmission
case.

Make sure that no oil gets on the
tire or wheel.
7. Check the final transmission case
for oil leakage. If oil is leaking,
check for the cause.
1. Final transmission oil filler cap
1. Final transmission oil drain bolt
Tightening torque:
Final transmission oil drain bolt:
23 Nm (2.3 m·kgf, 16.6 ft·lbf)
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Recommended final transmission
oil:
See page 8-1.
Oil quantity:
0.11 L (0.12 US qt) (0.10 Imp.qt)

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EAUT1843
Air filter and V-belt case air
filter elements
The air filter and V-belt case air filter el-
ements should be cleaned at the inter-
vals specified in the periodic
maintenance and lubrication chart.
Clean both filter elements more fre-
quently if you are riding in unusually
wet or dusty areas. The air filter check
hoses must be frequently checked and
cleaned if necessary.
Cleaning the air filter element
1. Place the scooter on the center-
stand.
2. Remove the air filter case cover by
removing the screws.3. Pull the air filter element out, and
then blow the dirt out with com-
pressed air as shown.
4. Check the air filter element fordamage and replace it if neces-
sary.
5. Insert the air filter element into the
air filter case.
CAUTION:

ECA10480

Make sure that the air filter ele-
ment is properly seated in the
air filter case.

The engine should never be op-
erated without the air filter ele-
ment installed, otherwise the
piston(s) and/or cylinder(s) may
become excessively worn.
6. Install the air filter case cover by in-
stalling the screws.
Cleaning the air filter check hoses
1. Check the hoses on the front and
rear side of the air filter case for ac-
cumulated dirt or water.
2. If dirt or water is visible, remove
the hoses, clean them, and then
install them.
Cleaning the V-belt case air filter el-
ement
1. Remove the V-belt air filter case

1. Air filter case cover
2. Screw
3. Air filter check hose
1. Air filter element
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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
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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

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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.
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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.