2003 YAMAHA SLIDER 50 engine

PERIODIC MAINTENANCE AND MINOR REPAIR
6
EAU01651
Checking the spark plug
The spark plug is an important engine
component, which should be checked
periodically, preferably by a Yamaha
dealer. Since heat and deposits will
cause any spark plug to slowly erode,
it should be removed and checked in
accordance with the periodic mainte-
nance and lubrication chart. In addition,
the condition of the spark plug can
reveal the condition of the engine.The porcelain insulator around the
center electrode of the spark plug
should be a medium-to-light tan (the
ideal color when the scooter is ridden
normally). If the spark plug shows a
distinctly different color, the engine
could be defective. Do not attempt to
diagnose such problems yourself.
Instead, have a Yamaha dealer check
the scooter.
If the spark plug shows signs of
electrode erosion and excessive
carbon or other deposits, it should be
replaced.
Specified spark plug:
BR8HS (NGK)
or BR9HS (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:
0.5 - 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:
20 Nm (2.0 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.
a
ZAUM0037
a. Spark plug gap
6-5

PERIODIC MAINTENANCE AND MINOR REPAIR
6
12
ZAUM0153
1. Final transmission oil drain bolt
2. Final transmission oil filler cap
EAU04228
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.
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.
Tightening torque:
Final transmission oil drain bolt:
17 Nm (1.7 m
•kgf)
6. Add the specified amount of the
recommended final transmission
oil, and then install and tighten the
oil filler cap.
Recommended final transmission oil:
See page 8-1.
Oil quantity:
0.11 L
EWA00062
•Make sure that no foreign
material enters the final trans-
mission case.
•Make sure that no oil gets on
7. Check the final transmission case
for oil leakage. If oil is leaking,
check for the cause.
6-6

PERIODIC MAINTENANCE AND MINOR REPAIR
6
1
ZAUM0170
1
ZAUM0318
1
4 32
ZAUM0156
1. Air filter case cover1. Air filter element
EAUM0071
Cleaning the air filter element
The air filter element should be cleaned
at the intervals specified in the periodic
maintenance and lubrication chart.
Clean the air filter element more
frequently if you are riding in unusually
wet or dusty areas.
1. Remove the air filter case cover
by removing the screws.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.
EC000089
To avoid damaging the foam material,
handle it gently and carefully, and do
not twist or wring it.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
6-7

PERIODIC MAINTENANCE AND MINOR REPAIR
6
EAU00631
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
ZAUM0051
a. Throttle cable free play
EAU00635
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. 4. Insert the element into the air filter
case.
EC000082
•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
EAUM0008
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.
EAU02962
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
cables and cable ends should be
lubricated if necessary. If a cable is
damaged or does not move smoothly,
have a Yamaha dealer check or replace
it.
Recommended lubricant:
Engine oil
EW000112
Damage to the outer sheath may
interfere with proper cable operation
and will cause the inner cable to
rust. Replace a damaged cable as
soon as possible to prevent unsafe
conditions.
6-14
•Brake fluid may deteriorate painted
surfaces or plastic parts. Always
clean up spilled fluid immediately.
•As the brake pads wear, it is nor-
mal for the brake fluid level to
gradually go down. However, if the
brake fluid level goes down
suddenly, have a Yamaha dealer
check the cause.

PERIODIC MAINTENANCE AND MINOR REPAIR
6
EAU02939
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
EW000115
Securely support the scooter 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 scooter on a level sur-
face and hold it in an upright po-
sition.
2. While applying the front brake,
push down hard on the
handlebars several times to check
if the front fork compresses and
rebounds smoothly.
EC000098
If any damage is found or the front
fork does not operate smoothly,
have a Yamaha dealer check or
repair it.
ZAUM0159
EAU00794
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.
EW000115
Securely support the scooter so that
there is no danger of it falling over.
6-16

PERIODIC MAINTENANCE AND MINOR REPAIR
6
6-22
EAU03473
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 fluid, recharge,
check connections..
Dry
WetOpen the throttle halfway and operate
the electric starter.

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.CleaningECA00011
•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.
7-1