2004 YAMAHA YFM50S engine

8-7
EBU00262
PERIODIC MAINTENANCE/LUBRICATION
INITIAL EVERY
ITEM ROUTINE 1 3 6 6 1
month months months months year
Valves*9Check valve clearance.
9Adjust if necessary.2 222
Cam chain*9Check chain tension.
9Adjust if necessary.2 222
9Check condition.
Spark plug9Adjust gap and clean.22222
9Replace if necessary.
Air filter element9Clean. Every 20–40 hours.
9Replace if necessary. (more often in wet or dusty areas)
Carburetor*9Check idle speed/choke lever operation.
2222
9Adjust if necessary.
Crankcase breather9Check breather hose for cracks or damage.
system*9Replace if necessary.222
9Check for leakage.
Exhaust system*9Tighten if necessary.222
9Replace gasket if necessary.
Fuel line*9Check fuel hose for cracks or damage.
222
9Replace if necessary.
Engine oil9Replace (warm engine before draining).2 222
Final gear oil9Check oil level/oil leakage.
22
9Replace every 12 months.
Brakes*9Check operation.
22222
9Adjust if necessary.
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8-13
EBU14181
Engine oil
Engine oil level measurement
1. Place the ATV on a level surface.
2. Warm up the engine for several minutes
and stop it.
3. Remove the dipstick and wipe it off with a
clean rag. Insert the dipstick in the filler
hole without screwing it in.
NOTE:
Wait a few minutes until the oil level settles
before checking.
4. Remove the dipstick and inspect the oil
level.
5. The oil level should be between the mini-
mum and maximum marks. If the level is
low, add oil to raise it to the specified level.
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Be sure no foreign material enters the
crankcase.
12
3
1. Dipstick
2. Maximum level mark 3. Minimum level mark
1. Jauge
2. Repère de niveau maximum 3. Repère de niveau minimum
1. Varilla de medición
2. Marca de máximo 3. Marca de mínimo
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8-15
Engine oil replacement
1. Place the ATV on a level surface.
2. Warm up the engine for several minutes
and stop it.
3. Place a container under the engine.
4. Remove the dipstick and drain bolt to drain
the oil.
5. Inspect the O-ring and replace if damaged.
6. Install the drain bolt and tighten to specifi-
cation.
1
1. Drain bolt1. Bouchon de vidange1. Perno de drenaje
Tightening torque
Drain bolt:
20 Nm (2.0 m0kgf)
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8-17
7. Fill the engine with oil and install the dip-
stick.
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Be sure no foreign material enters the
crankcase.
8. Warm up the engine for several minutes at
idle speed. Check for oil leakage while
warming up.
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If oil leakage is found, stop the engine imme-
diately and check for the cause.
Recommended oil type:
20W50, 20W40, 15W40, 10W40,
10W30, 5W30
Recommended oil classification:
API Service SE, SF, SG type or higher
Oil quantity:
Periodic oil change:
0.8L
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8-23
EBU11820
Spark plug inspection
The spark plug is an important engine compo-
nent and is easy to inspect. The condition of the
spark plug can indicate the condition of the
engine.
For example, a very white center electrode
porcelain color could indicate an intake air leak
or carburetion problem for that cylinder. Do not
attempt to diagnose such problems yourself.
Instead, take the ATV to a Yamaha dealer. You
should periodically remove and inspect the
spark plug because heat and deposits will cause
the spark plug to slowly break down and erode.
If electrode erosion becomes excessive, you
should replace the spark plug with one of the
proper type.
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2
1
1. Fastener 2. Air filter element1. Attache 2. Elément du filtre à air1. Sujeción 2. Elemento filtrante de aire
8-29
2. Remove the air filter case cover by
unhooking the fasteners.
3. Remove the air filter element by unhooking
the fastener.
4. Wash the air filter element gently but thor-
oughly in solvent.
w
Always use parts cleaning solvent to clean
the air filter element. Never use low flash
point solvents or gasoline to clean the air fil-
ter element because the engine could catch
fire or explode.
5. Squeeze the excess solvent out of the air
filter element and let it dry.
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Do not twist the air filter element when
squeezing it.
6. Inspect the air filter element. If damaged,
replace it.
7. Apply Yamaha foam air filter oil or other
quality foam air filter oil to the air filter ele-
ment. If foam air filter oil is not available,
SAE10W30 motor oil may be used.
q
ww
1. Air filter case cover 2. Fastener (×4)1 . Couvercle du boîtier de filtre à air 2 .Attache (×4)1.Cubierta de la caja del filtro de aire2. Sujeción (×4)
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8-31
NOTE:
The air filter element should be wet but not drip-
ping.
8. Install the air filter element.
9. Install the air filter case cover by hooking
the fasteners onto the air filter case.
10. Install the front cover by installing the bolts.
NOTE:
The air filter element should be cleaned every
20-40 hours. It should be cleaned and lubricated
more often if the machine is operated in
extremely dusty areas. Each time air filter ele-
ment maintenance is performed, check the air
inlet of the air filter case for obstructions. Check
the air cleaner rubber joint to the carburetor and
manifold fittings for an airtight seal. Tighten all
fittings securely to avoid the possibility of unfil-
tered air entering the engine.
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8-33
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Never operate the engine with the air filter
element removed. This will allow unfiltered
air to enter the engine, causing rapid engine
wear and possible engine damage.
Additionally, operation without the filter ele-
ment will affect carburetor jetting with sub-
sequent poor performance and possible
engine overheating.
5YF-9-60 8 4/24/03 6:35 PM Page 8-33