2007 YAMAHA CYGNUS 125 engine

OPERATION AND IMPORTANT RIDING POINTS
5-4
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EAU17212
Parking
When parking, stop the engine, and
then remove the key from the main
switch.
WARNING

EWA10310

Since the engine and exhaust
system can become very hot,
park in a place where pedestri-
ans or children are not likely to
touch them.

Do not park on a slope or on soft
ground, otherwise the vehicle
may overturn.
CAUTION:

ECA10380
Never park in an area where there
are fire hazards such as grass or
other flammable materials.

6-1
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PERIODIC MAINTENANCE AND MINOR REPAIR
EAU17280
Safety is an obligation of the owner. Pe-
riodic inspection, adjustment and lubri-
cation will keep your vehicle in the
safest and most efficient condition pos-
sible. The most important points of in-
spection, adjustment, and lubrication
are explained on the following pages.
The intervals given in the periodic
maintenance and lubrication chart
should be simply considered as a gen-
eral guide under normal riding condi-
tions. However, DEPENDING ON THE
WEATHER, TERRAIN, GEOGRAPHI-
CAL LOCATION, AND INDIVIDUAL
USE, THE MAINTENANCE INTER-
VALS MAY NEED TO BE SHORT-
ENED.
WARNING

EWA10320
If you are not familiar with mainte-
nance work, have a Yamaha dealer
do it for you.
WARNING

EWA10330
This scooter is designed for use on
paved roads only. If this scooter isoperated in abnormally dusty, mud-
dy or wet conditions, the air filter el-
ement should be cleaned or
replaced more frequently, otherwise
rapid engine wear may result. Con-
sult a Yamaha dealer for proper
maintenance intervals.
EAU17520
Owner’s tool kit
The owner’s tool kit is located inside the
storage compartment under the seat.
(See page 3-9.)
The service information included in this
manual and the tools provided in the
owner’s tool kit are intended to assist
you in the performance of preventive
maintenance and minor repairs. How-
ever, additional tools such as a torque
wrench may be necessary to perform
certain maintenance work correctly.
NOTE:

If you do not have the tools or experi-
ence required for a particular job, have
1. Owner’s tool kit
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PERIODIC MAINTENANCE AND MINOR REPAIR
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9

10

*
Tires

Check tread depth and for damage.

Replace if necessary.

Check air pressure.

Correct if necessary.
√√√√ √
11

*
Wheel bearings

Check bearing for looseness or damage.
√√√√
12

*
Steering bearings

Check bearing play and steering for roughness.
√√√√√

Lubricate with lithium-soap-based grease. Every 24000 km
13

*
Chassis fasteners

Make sure that all nuts, bolts and screws are properly
tightened.
√√√√ √
14

Sidestand, centerstand

Check operation.

Lubricate.
√√√√ √
15

*
Sidestand switch

Check operation.
√√√√√ √
16

*
Front fork

Check operation and for oil leakage.
√√√√
17

*
Shock absorber assem-
bly

Check operation and shock absorber for oil leakage.
√√√√
18

*
Fuel injection

Check engine idle speed.
√√√√√ √
19

Engine oil

Change. (See page 6-9.)

Check oil level and vehicle for oil leakage.
√
Every 3000 km
20

*
Engine oil strainer

Clean.
√
21

Final transmission oil

Check vehicle for oil leakage.
√√ √

Change.
√√√
22

*
V-belt

Replace. Every 18000 km
23

*
Front and rear brake
switches

Check operation.
√√√√√ √
24

Moving parts and cables

Lubricate.
√√√√ √
25

*
Throttle grip housing
and cable

Check operation and free play.

Adjust the throttle cable free play if necessary.

Lubricate the throttle grip housing and cable.
√√√√ √
NO. ITEM CHECK OR MAINTENANCE JOBODOMETER READING (
×
1000 km)
ANNUAL
CHECK
1 6 12 18 24

PERIODIC MAINTENANCE AND MINOR REPAIR
6-7
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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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PERIODIC MAINTENANCE AND MINOR REPAIR
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8
9 To check the spark plug
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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PERIODIC MAINTENANCE AND MINOR REPAIR
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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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PERIODIC MAINTENANCE AND MINOR REPAIR
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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)

PERIODIC MAINTENANCE AND MINOR REPAIR
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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)