YAMAHA CYGNUS 125 2011 Service Manual

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EAU1722A
PERIODIC MAINTENANCE AND ADJUSTMENT
EAUT2710
TIP● Air fi lter and V-belt fi lter
• This model’s air fi lter is equipped with a disposable oil-coated paper element, which must not be cleaned with
compressed air to avoid damaging it.
• The air fi lter element needs to be replaced and V-belt fi lter needs to be serviced more frequently when riding in
unusually wet or dusty areas.● Hydraulic brake service
• After disassembling the brake master cylinder and caliper, always change the fl uid. Regularly check the brake
fl uid level and fi ll the reservoir as required.
• Every two years replace the internal components of the brake master cylinder and caliper, and change the brake
fl uid.
• Replace the brake hose every four years and if cracked or damaged.
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EAU1722A
PERIODIC MAINTENANCE AND ADJUSTMENT
EAU18771
Removing and installing pan-
elsThe panels shown need to be re-
moved to perform some of the mainte-
nance jobs described in this chapter.
Refer to this section each time a panel
needs to be removed and installed.ZAUM00**
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3 4
1. Panel A
2. Panel B
3. Panel C
4. Panel D
EAUT1882
Panel A
To remove the panelRemove the screws, and then take
the panel off.ZAUM00**
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2✕(8)
1. Panel A
2. ScrewTo install the panelPlace the panel in the original posi-
tion, and then install the screws.Panel B
To remove the panel
Remove the screws, and then take
the panel off.ZAUM00**1
2✕(2)
1. Panel B
2. ScrewTo install the panelPlace the panel in the original posi-
tion, and then install the screws.
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EAU1722A
PERIODIC MAINTENANCE AND ADJUSTMENT
Panel C
To remove the panelRemove the screws, and then take
the panel off.ZAUM00**
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1. Panel C
2. ScrewTo install the panelPlace the panel in the original posi-
tion, and then install the screws.Panel D
To remove the panel
1. Open the seat. (See page 3-10.)ZAUM00**
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1. Panel D
2. Screw2. Remove the quick fasteners by
pushing in the center pin, and
then take the panel off.
To install the panelPlace the panel in the original posi-
tion, and then install quick fasteners.
EAUT1835
Checking the spark plugThe 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 pe-
riodic maintenance and lubrication
chart. In addition, the condition of the
spark plug can reveal the condition of
the engine.
To remove the spark plug
1. Place the vehicle on the center-
stand.
2. Remove panel C. (See page 6-8.)
3. Remove the spark plug cap.
4. Remove the spark plug as
shown, with the spark plug
wrench included in the owner’s
tool kit.
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EAU1722A
PERIODIC MAINTENANCE AND ADJUSTMENTZAUM00**
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1. Spark plug wrenchTo check the spark plug
1. Check that the porcelain insula-
tor around the center electrode
of the spark plug is a medium-to-
light tan (the ideal color when the
vehicle is ridden normally).TIPIf the spark plug shows a distinctly
different color, the engine could be
operating improperly. Do not attempt
to diagnose such problems yourself.
Instead, have a Yamaha dealer check
the vehicle.
2. Check the spark plug for elec-
trode erosion and excessive carbon or other deposits, and re-
place it if necessary.
Speci ed spark plug:
CR7E (NGK)To install the spark plug
1. Measure the spark plug gap with
a wire thickness gauge and, if
necessary, adjust the gap to
specifi cation.ZAUM00**
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1. Spark plug gapSpark plug gap:
0.7 ~ 0.8 mm (0.028 ~ 0.031 in)2. Clean the surface of the spark
plug gasket and its mating sur-
face, and then wipe off any grime
from the spark plug threads.
3. Install the spark plug with the
spark plug wrench, and then
tighten it to the specifi ed torque.Tightening torque:
Spark plug:
13 Nm (1.3 m·kgf, 9.4 ft·lbf)TIPIf a torque wrench is not available
when installing a spark plug, a good
estimate of the correct torque is 1/4 ~
1/2 turn past fi nger tight. However, the
spark plug should be tightened to the
specifi ed torque as soon as possible.
4. Install the spark plug cap.
5. Install the panel.
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6-10
EAU1722A
PERIODIC MAINTENANCE AND ADJUSTMENT
EAUT1352
Engine oil and oil strainerThe engine oil level should be
checked before each ride. In addition,
the oil must be changed and the oil
strainer cleaned at the intervals speci-
fi ed 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 indi-
cator fl ashes. The oil change tripmeter
must be reset after the initial 1000 km
(600 mi). (See page 3-3 for reset pro-
cedures.)
To check the engine oil level
1. Place the vehicle on the center-
stand. 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
settles, remove the oil fi ller cap,
wipe the dipstick clean, insert it
back into the oil fi ller hole (without
screwing it in), and then remove it
again to check the oil level.
TIPThe engine oil should be between the
minimum and maximum level marks.ZAUM00**
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1. Maximum level mark
2. Minimum level mark4. If the engine oil is below the mini-
mum level mark, add suffi cient oil
of the recommended type to raise
it to the correct level.
5. Insert the dipstick into the oil fi ller
hole, and then tighten the oil fi ller
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 fi ller cap
and drain bolts to drain the oil
from the crankcase.
NOTICE:

When removing the engine oil
drain bolt, the O-ring, spring,
and oil strainer will fall out.
Take care not to lose these
parts.
[ECA10411]
ZAUM00**
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1. Oil fi ller cap
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EAU1722A
PERIODIC MAINTENANCE AND ADJUSTMENTZAUM00**
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1. Engine oil drain bolt AZAUM00**
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1. Engine oil drain bolt B4. 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 specifi ed torque.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)TIPMake sure that the O-ring is properly
seated.
7. Refi ll with the specifi ed amount of
the recommended engine oil, and
then install and tighten the engine
oil fi ller cap.Recommended engine oil:
See page 8-1.
Oil change quantity:
0.9 L (0.95 US qt, 0.79 Imp.qt)
ECA11670
NOTICE● Do not use oils with a diesel
speci cation of “CD” or oils of
a higher quality than speci ed.
In addition, do not use oils la-
beled “ENERGY CONSERVING
II” or higher.
● 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, immediately turn the en-
gine 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 3-3 for reset proce-
dures.)
TIPIf the engine oil is changed before
the oil change indicator fl ashes (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 indicated at the correct
time.
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EAU1722A
PERIODIC MAINTENANCE AND ADJUSTMENT
EAU20065
Final transmission oilThe fi nal 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 fi nal transmis-
sion oil must be changed as follows at
the intervals specifi ed in the periodic
maintenance and lubrication chart.
1. Start the engine, warm up the fi -
nal 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 fi nal
transmission case to collect the
used oil.
ZAUM00**
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1. Final transmission oil fi ller cap4. Remove the fi nal transmission oil
fi ller cap and its O-ring from the
fi nal transmission case.
5. Remove the fi nal transmission oil
drain bolt and its gasket to drain
the oil from the fi nal transmission
case.
ZAUM00**
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1. Final transmission oil drain bolt6. Install the fi nal transmission oil
drain bolt and its new gasket, and
then tighten the bolt to the speci-
fi ed torque.Tightening torque:
Final transmission oil drain bolt:
23 Nm (2.3 m·kgf, 16.6 ft·lbf)7. Refi ll with the specifi ed amount of
the recommended fi nal transmis-
sion oil. WARNING! Make sure
that no foreign material enters
the nal transmission case.
Make sure that no oil gets on
the tire or wheel.
[EWA11311]
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6-13
EAU1722A
PERIODIC MAINTENANCE AND ADJUSTMENTRecommended nal transmission
oil:
See page 8-1.
Oil quantity:
0.11 L (0.12 US qt, 0.10 Imp.qt)8. Install the fi nal transmission oil
fi ller cap and its new O-ring, and
then tighten the oil fi ller cap.
9. Check the fi nal transmission case
for oil leakage. If oil is leaking,
check for the cause.
EAUT3120
Air lter and V-belt case air
lter elementsThe air fi lter and V-belt case air fi lter
elements should be cleaned at the in-
tervals specifi ed in the periodic main-
tenance and lubrication chart. Check
both fi lter elements more frequently
if you are riding in unusually wet or
dusty areas. The air fi lter check hoses
must be frequently checked and
cleaned if necessary.
Replacing the air lter element
1. Place the scooter on the center-
stand.2. Remove the air fi lter case cover
by removing the screws.
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1. Air fi lter case cover
2. Screw3. Pull the air fi lter element out.
4. Insert a new air fi lter element into
the air fi lter case.
NOTICE:
Make
sure that the air lter element
is properly seated in the air
lter case. The engine should
never be operated without
the air lter element installed,
otherwise the piston(s) and/or
cylinder(s) may become exces-
sively worn.
[ECA10481]
5. Install the air fi lter case cover by
installing the screws.
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EAU1722A
PERIODIC MAINTENANCE AND ADJUSTMENT
Cleaning the air lter check hoses
1. Check the hoses on the front and
rear side of the air fi lter case for
accumulated dirt or water.ZAUM00**
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1. Air fi lter check hose2. If dirt or water is visible, remove
the hoses, clean them, and then
install them.Cleaning the V-belt case air lter
element
1. Remove the V-belt air fi lter case
cover by removing the screws.
ZAUM00**
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1. V-belt air fi lter case cover2. Remove the fi lter element holder
by removing the screw.ZAUM00**
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1. Air fi lter element holder
3. Pull the air fi lter element out, and
then clean it with solvent. After
cleaning, remove the remain-
ing solvent by squeezing the
element. WARNING! Use only a
dedicated parts cleaning sol-
vent. To avoid the risk of re or
explosion, do not use gasoline
or solvents with a low ash
point.
[EWA10431]
NOTICE:
To avoid
damaging the air lter element,
handle it gently and carefully,
and do not twist it.
[ECA10521]
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1. V-belt case air fi lter element4. Apply oil of the recommended
type to the entire surface of
the sponge material, and then
squeeze the excess oil out.
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EAU1722A
PERIODIC MAINTENANCE AND ADJUSTMENTTIPThe air fi lter element should be wet
but not dripping.Recommended oil:
Yamaha foam air fi lter oil or other
quality foam air fi lter oil5. Insert the element into the air fi l-
ter case.
6. Install the fi lter element holder by
installing the screw.
7. Install the V-belt air fi lter case
cover by installing the screws.
EAU21401
Valve clearanceThe valve clearance changes with
use, resulting in improper air-fuel mix-
ture and/or engine noise. To prevent
this from occurring, the valve clear-
ance must be adjusted by a Yamaha
dealer at the intervals specifi ed in the
periodic maintenance and lubrication
chart.
EAU21384
Checking the throttle grip
free playThe throttle grip free play should mea-
sure 3 ~ 5 mm (0.12 ~ 0.20 in) at the
inner edge of the throttle grip. Periodi-
cally check the throttle grip free play
and, if necessary, have a Yamaha
dealer adjust it.ZAUM00**
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1. Throttle cable free play
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