2004 YAMAHA WHY 50 engine

PERIODIC MAINTENANCE AND MINOR REPAIR
6 If the spark plug shows signs of
electrode erosion and excessive
carbon or other deposits, it should be
replaced.
Specified spark plug:
BR8HS (NGK)
Before installing a spark plug, the spark
plug gap should be measured with a
wire thickness gauge and, if necessary,
adjusted to specification.
Spark plug gap:
0.6 — 0.7 mmClean the surface of the spark plug
gasket and its mating surface, and then
wipe off any grime from the spark plug
threads.
Tightening torque:
Spark plug:
23 Nm (2.3 m
•kg)
NOTE :
If 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 finger tight. However, the spark
plug should be tightened to the
specified torque as soon as possible.
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a Spark plug gap
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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 it up by
riding the scooter for several mi-
nutes, and then stop the engine.
2. Place the scooter on the
centerstand.
3. Place an oil pan under the final
transmission case to collect the
used oil.
6-6

PERIODIC MAINTENANCE AND MINOR REPAIR
6 2. Pull the air filter element out, clean
it with solvent, and then squeeze
the remaining solvent out.EW000075
Use only a dedicated parts cleaning
solvent. To avoid the risk of fire or
explosion, do not use gasoline or
solvents with a low flash point.
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To avoid damaging the foam material,
handle it gently and carefully, and do
not twist or wring it.
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4 32
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3. Apply oil of the recommended
type to the entire surface of the
element, and then squeeze the
excess oil out.
NOTE :
The air filter element should be wet but
not dripping
Recommended oil:
Engine oil
4. Insert the element into the air filter
case.
1. Air filter element
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•Make sure that the air filter
element is properly seated in
the air filter case.
•The engine should never be
operated without the air filter
element installed, otherwise the
piston(s) and/or cylinder(s)
may become excessively worn.
5. Install the air filter case cover by
installing the screws.
6-8

PERIODIC MAINTENANCE AND MINOR REPAIR
6
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Adjusting the carburetor
The carburetor is an important part of
the engine and requires very
sophisticated adjustment. Therefore, all
carburetor adjustments should be left
to a Yamaha dealer, who has the
necessary professional knowledge and
experience.
a
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Adjusting the throttle cable
free play
The throttle cable free play should
measure 1.5 — 3.0 mm at the throttle
grip. Periodically check the throttle cable
free play and, if necessary, have a
Yamaha dealer adjust it.
a Throttle cable free play
6-9

PERIODIC MAINTENANCE AND MINOR REPAIR
6
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Changing the brake fluid
Have a Yamaha dealer change the
brake fluid at the intervals specified in
the periodic maintenance and
lubrication chart. In addition, have the
brake hose replaced every four years
or whenever it is damaged or leaking.
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Checking and lubricating the
throttle grip and cable
The operation of the throttle grip should
be checked before each ride. In addi-
tion, the cable should be lubricated or
replaced at the intervals specified in the
periodic maintenance chart.
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Adjusting the Autolube pump
The Autolube pump is a vital and
sophisticated component of the engine,
which must be adjusted by a Yamaha
dealer at the intervals specified in the
periodic maintenance and lubrication
chart.
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Lubricating the front and rear
brake levers
The pivoting points of the front and rear
brake levers must be lubricated at the
intervals specified in the periodic main-
tenance and lubrication chart.
Recommended lubricant:
Lithium-soap-based grease
(all-purpose grease)

PERIODIC MAINTENANCE AND MINOR REPAIR
6
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Checking the wheel bearings
The front and rear wheel bearings must
be checked at the intervals specified in
the periodic maintenance and
lubrication chart. If there is play in the
wheel hub or if the wheel does not turn
smoothly, have a Yamaha dealer check
the wheel bearings.
6-17
2. Hold the lower ends of the front
fork legs and try to move them
forward and backward. If any free
play can be felt, have a Yamaha
dealer check or repair the
steering.
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Checking the steering
Worn or loose steering bearings may
cause danger. Therefore, the operation
of the steering must be checked as
follows at the intervals specified in the
periodic maintenance and lubrication
chart.
1. Place a stand under the engine
to raise the front wheel off the
ground.
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Securely support the scooter so that
there is no danger of it falling over.

PERIODIC MAINTENANCE AND MINOR REPAIR
6
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Troubleshooting chartEW000125
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. FuelThere 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. CompressionThere 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. IgnitionWipe 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. BatteryThe engine turns over
quickly.
The engine turns over
slowly.The battery is good.
Check the battery lead connections,
and charge the battery if necessary.
Dry
WetOpen the throttle halfway and operate
the electric starter.
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SCOOTER CARE AND STORAGE
7
Care
While the open design of a scooter
reveals the attractiveness of the
technology, 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 overall
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
plastic bag after the engine has
cooled down.
2. Make sure that all caps and covers
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
products onto seals, gaskets and
wheel axles. Always rinse the dirt
and degreaser off with water.
Cleaning
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•Avoid 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.
•Improper 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.
•Do 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 products, solvent or
thinner, fuel (gasoline), rust
removers or inhibitors, brake
fluid, antifreeze or electrolyte.
•Do not use high-pressure
washers or steam-jet cleaners
since they cause water seepage
and deterioration in the following
areas: seals (of wheel and
swingarm bearings, fork and
brakes), electric components
(couplers, connectors, instru-
ments, switches and lights),
breather hoses and vents.
7-1

SCOOTER CARE AND STORAGE
7
•For 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
compound after washing.
After normal use
Remove dirt with warm water, a mild
detergent, and a soft, clean sponge,
and then rinse thoroughly with clean
water. Use a toothbrush or bottlebrush
for hard-to-reach areas. Stubborn dirt
and insects will come off more easily if
the area is covered with a wet cloth for
a few minutes before cleaning.
After riding in the rain, near the sea
or on salt-sprayed roads
Since sea salt or salt sprayed on the
roads during winter are extremely cor-
rosive in combination with water, carry
out the following steps after each ride
in the rain, near the sea or on salt-
sprayed roads.
NOTE :
Salt sprayed on roads in the winter may
remain well into spring.
1. Clean the scooter with cold water
and a mild detergent after the
engine has cooled down.
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Do not use warm water since it
increases the corrosive action of the
salt.
2. Apply a corrosion protection spray
on all metal, including chrome-
and nickel-plated, surfaces to
prevent corrosion.After cleaning
1. Dry the scooter with a chamois or
an absorbing cloth.
2. Use a chrome polish to shine
chrome, aluminum and stainless-
steel parts, including the exhaust
system. (Even the thermally
induced discoloring of stainless-
steel exhaust systems can be
removed through polishing.)
3. To prevent corrosion, it is
recommended to apply a corro-
sion protection spray on all metal,
including chrome- and nickel-
plated, surfaces.
4. Use spray oil as a universal
cleaner to remove any remaining
dirt.
5. Touch up minor paint damage
caused by stones, etc.
6. Wax all painted surfaces.
7. Let the scooter dry completely
before storing or covering it.
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