2005 YAMAHA CYGNUS 125 engine

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PERIODIC MAINTENANCE AND MINOR REPAIR
EAU25901
Troubleshooting chart
EWA10840
wKeep 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
Open the throttle halfway and operate
the electric starter.
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SCOOTER CARE AND STORAGE
EAU26090
CareWhile the open design of a scooter re-
veals the attractiveness of the technol-
ogy, it also makes it more vulnerable.
Rust and corrosion can develop even if
high-quality components are used. A
rusty exhaust pipe may go unnoticed on
a car, however, it detracts from the over-
all appearance of a scooter. Frequent and
proper care does not only comply with
the terms of the warranty, but it will also
keep your scooter looking good, extend
its life and optimize its performance.
Before cleaning
1. Cover the muffler outlet with a plas-
tic bag after the engine has cooled
down.
2. Make sure that all caps and cov-
ers as well as all electrical couplers
and connectors, including the spark
plug cap, are tightly installed.
3. Remove extremely stubborn dirt,
like oil burnt onto the crankcase,
with a degreasing agent and a
brush, but never apply such prod-ucts onto seals, gaskets and wheel
axles. Always rinse the dirt and
degreaser off with water.
Cleaning
ECA10780
cC8 88 8
8Avoid using strong acidic wheel
cleaners, especially on spoked
wheels. If such products are used
on hard-to-remove dirt, do not
leave the cleaner on the affected
area any longer than instructed.
Also, thoroughly rinse the area
off with water, immediately dry
it, and then apply a corrosion
protection spray.
8 88 8
8Improper cleaning can damage
windshields, cowlings, panels
and other plastic parts. Use only
a soft, clean cloth or sponge with
mild detergent and water to clean
plastic.
8 88 8
8Do not use any harsh chemical
products on plastic parts. Be sure
to avoid using cloths or sponges
which have been in contact with
strong or abrasive cleaning prod-ucts, solvent or thinner, fuel
(gasoline), rust removers or in-
hibitors, brake fluid, antifreeze or
electrolyte.
8 88 8
8Do not use high-pressure wash-
ers or steam-jet cleaners since
they cause water seepage and
deterioration in the following ar-
eas: seals (of wheel and
swingarm bearings, fork and
brakes), electric components
(couplers, connectors, instru-
ments, switches and lights),
breather hoses and vents.
8 88 8
8For scooters equipped with a
windshield: Do not use strong
cleaners or hard sponges as they
will cause dulling or scratching.
Some cleaning compounds for
plastic may leave scratches on
the windshield. Test the product
on a small hidden part of the
windshield to make sure that it
does not leave any marks. If the
windshield is scratched, use a
quality plastic polishing com-
pound after washing.
EAU25990
SCOOTER CARE AND STORAGE
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SCOOTER CARE AND STORAGE
8 88 8
8Avoid using abrasive polishing
compounds as they will wear
away the paint.NOTE:
Consult a Yamaha dealer for advice on
what products to use.
EAU26300
StorageShort-term
Always store your scooter in a cool, dry
place and, if necessary, protect it
against dust with a porous cover.
ECA10820
cC8 88 8
8Storing the scooter in a poorly
ventilated room or covering it
with a tarp, while it is still wet,
will allow water and humidity to
seep in and cause rust.
8 88 8
8To prevent corrosion, avoid
damp cellars, stables (because of
the presence of ammonia) and
areas where strong chemicals are
stored.Long-term
Before storing your scooter for several
months:
1. Follow all the instructions in the
“Care” section of this chapter.
2. Drain the carburetor float chamber
by loosening the drain bolt; this will
prevent fuel deposits from building
up. Pour the drained fuel into the
fuel tank.3. Fill up the fuel tank and add fuel
stabilizer (if available) to prevent the
fuel tank from rusting and the fuel
from deteriorating.
4. 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.
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SCOOTER CARE AND STORAGE
EWA10950
wTo prevent damage or injury from
sparking, make sure to ground the
spark plug electrodes while turning
the engine over.5. Lubricate all control cables and the
pivoting points of all levers and
pedals as well as of the sidestand/
centerstand.
6. 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.
7. Cover the muffler outlet with a plas-
tic bag to prevent moisture from en-
tering it.
8. 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 excessively 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 6-23.
NOTE:
Make any necessary repairs before stor-
ing the scooter.
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SPECIFICATIONS
-20˚ -10˚ 0˚ 10˚ 20˚ 30˚ 40˚ 50˚
SAE 10W-30SAE 10W-40
SAE 20W-40SAE 20W-50
ZAUM00**
EAU26320
SPECIFICATIONS
EAU26339
DimensionsOverall length
1855 mm
Overall width
685 mm
Overall height
1110 mm
Seat height
770 mm
Wheelbase
1295 mm
Ground clearance
110 mm
Minimum turning radius
1900 mmWeightWith oil and fuel
121.0 kgEngineEngine type
Forced air cooled 4-stroke, SOHC
Cylinder arrangement
Forward-inclined single cylinder
Displacement
124.0 cm
3
Bore & stroke
52.4 x 57.9 mm
Compression ratio
10.00 :1
Starting system
Electric starter and kickstarter
Lubrication system
Wet sump
Engine oilType
SAE20W40
Recommended engine oil grade
API service SE, SF, SG type or higher
Engine oil quantity
Periodic oil change
0.90 L
Without oil filter element removal
0.90 LFinal transmission oilType
SAE10W30 type SE motor oil
Quantity
0.13 LAir filterAir filter element
Oil-coated paper elementFuelRecommended fuel
Regular unleaded gasoline only
Fuel tank capacity
7.1 L
CarburetorManufacturer
Taiwan KEI HIN
Type x quantity
CVK24 x 1Spark plug(s)Manufacturer/model
NGK / CR7E
Spark plug gap
0.6-0.7 mmClutchClutch type
Dry, centrifugal automaticTransmissionPrimary reduction system
Helical gear
Primary reduction ratio
38/13 (2.923)
Secondary reduction system
Helical gear
Secondary reduction ratio
40 / 12 (3.333)
Transmission type
V-belt automatic
Operation
Centrifugal automatic typeChassisFrame type
Steel tube underbone
Caster angle
27.00 degree
Trail
90.0 mm
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INDEXAAcceleration and deceleration.................. 5-2
Air filter and V-belt case air filter
elements................................................6-11BBattery.....................................................6-23
Brake fluid level, checking ......................6-19
Brake fluid, changing ..............................6-20
Brake lever, front ...................................... 3-4
Brake lever, rear....................................... 3-4
Brake levers, lubricating.........................6-21
Brake pads and shoes, checking..........6-18
Braking...................................................... 5-2CCables, checking and lubricating ...........6-20
Carburetor,adjusting...............................6-13
Catalytic converter................................... 3-6
Centerstand and sidestand, checking and lu-
bricating.................................................6-21DDimmer switch.......................................... 3-4EEngine break-in ......................................... 5-3
Engine oil and oil strainer .......................... 6-8FFinal transmission oil ..............................6-10
Front brake lever free play, checking....6-17
Fuel........................................................... 3-6
Fuel consumption, tips for reducing ......... 5-3
Fuel gauge ................................................ 3-3
Fuel tank cap ............................................ 3-5
Fuses, replacing.....................................6-25
HHandlebar switches.................................. 3-3
Headlight bulb, replacing........................6-26
Helmet holder............................................ 3-8
High beam indicator light .......................... 3-2
Horn switch............................................... 3-4IIdentification numbers.............................. 9-1
Indicator lights........................................... 3-2KKey identification number......................... 9-1
Kickstarter................................................ 3-7LLuggage hook........................................... 3-9MMain switch/steering lock......................... 3-1
Model label................................................ 9-2PPanels, 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
Rear brake lever free play, adjusting .....6-18SSafe-riding points...................................... 1-4
Safety information..................................... 1-1
Seat ........................................................... 3-7
Sidestand................................................3-10
Sidestand switch operation check .........3-10Spark plug, checking................................ 6-7
Specifications............................................ 8-1
Speedometer unit..................................... 3-3
Start switch............................................... 3-4
Starting a cold engine ............................... 5-1
Starting off ................................................. 5-2
Storage...................................................... 7-3
Storage compartment............................... 3-8
TTail/brake light bulb, replacing ................6-27
Throttle cable free play, adjusting..........6-14
Throttle grip and cable, checking and lubricat-
ing ..........................................................6-21
Tires........................................................6-15
Tool kit ....................................................... 6-1
Troubleshooting......................................6-29
Troubleshooting chart.............................6-30
Turn signal indicator light.......................... 3-2
Turn signal light bulb (front), replacing ...6-28
Turn signal switch ..................................... 3-4VValve clearance......................................6-14
Vehicle identification number .................... 9-1WWheel bearings, checking ......................6-23
Wheels....................................................6-17
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