2001 YAMAHA YFM660R check engine

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Starting a warm engine
To start a warm engine, refer to the “Starting a
cold engine” section. The starter (choke)
should not be used. The throttle should be
opened slightly.
EBU00538
Warming up
To get maximum engine life, always warm up
the engine before starting off. Never accelerate
hard with a cold engine! To see whether or not
the engine is warm, check if it responds to the
throttle normally with the starter (choke)
turned off.
NOTE:
When the parking brake is used, engine speed
is limited to 2,300 r/min. Be sure the parking
brake is released before moving the throttle le-
ver. Otherwise, the engine will misfire, pre-
venting normal operation.

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EBU00262
PERIODIC MAINTENANCE/LUBRICATION
ITEM ROUTINEINITIAL EVERY
1
month3
months6
months6
months1
year
Valves*• Check valve clearance.
• Adjust if necessary.
Cooling system• Check coolant leakage.
• Repair if necessary.
• Replace coolant every 24 months.
Spark plug• Check condition.
• Adjust gap and clean.
• Replace if necessary.
Air filter element• Clean.
• Replace if necessary.Every 20~40 hours
(More often in wet or dusty areas.)
Carburetor*• Check and adjust idle speed/starter operation.
• Adjust if necessary.
Crankcase breather
system*• Check breather hose for cracks or damage.
• Replace if necessary.
Exhaust system*• Check for leakage.
• Retighten if necessary.
• Replace gasket if necessary.
Fuel line*• Check fuel hose for cracks or damage.
• Replace if necessary.
Engine oil• Replace (Warm engine before draining.)
Engine oil filter cartridge• Replace if necessary.
Drive chain• Check and adjust slack/alignment/clean/lube.
Brakes*• Check operation/fluid leakage/See NOTE Page 8-8.
• Correct if necessary.
Clutch*• Check operation.
• Adjust if necessary.

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1. Engine oil tank
2. Engine oil filler cap
3. Maximum level mark
4. Minimum level mark
1. Réservoir d’huile de moteur
2. Bouchon de remplissage de l’huile de moteur
3. Repère de niveau maximum
4. Repère de niveau minimum
1. Depósito de aceite de motor
2. Tapa de relleno de aceite de motor
3. Marca de nivel máximo
4. Marca de nivel mínimo
EBU00812
Engine oil and oil filter cartridge
The engine oil level should be checked before
each ride. In addition, the oil must be changed
and the oil filter cartridge replaced at the inter-
vals specified in the periodic maintenance and
lubrication chart.
To check the engine oil level
1. Place the ATV on a level surface.
2. Start the engine, warm it up until the en-
gine oil has reached a normal tempera-
ture of 60˚C, let it continue to idle for ten
seconds, and then turn the engine off.
NOTE:
To achieve the proper engine oil temperature
for an accurate oil level reading, the engine
must have first completely cooled down, and
then warmed up again for several minutes to
normal operating temperature.
3. Wait a few minutes until the oil settles, re-
move the engine oil tank filler cap, wipe
the dipstick clean, insert it back into the
filler hole (without screwing it in), and
then remove it again to check the oil level.

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1. Engine oil crankcase drain bolt
1. Boulon de vidange du carter d’huile de moteur
1. Perno de drenaje de aceite de motor del cárter
4. Remove the crankcase drain bolt.
5. Check the washer for damage, and re-
place it if necessary.
6. Remove the engine oil tank filler cap and
the drain bolt.
NOTE:
Skip steps 7–8 if the oil filter cartridge is not be-
ing replaced.
1. Engine oil tank drain bolt
1. Boulon de vidange du réservoir d’huile de moteur
1. Perno de drenaje de aceite de motor del motor

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11. Start the engine, and then let it idle for
several minutes while checking it for oil
leakage. If oil is leaking, immediately turn
the engine off and check for the cause.
12. Turn the engine off, and then check the oil
level and correct it if necessary.

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Cooling system
1. Check the coolant level in the coolant res-
ervoir when the engine is cold as the cool-
ant level will vary with engine temperature.
The coolant level should be between the
maximum and minimum marks.
2. Remove the coolant reservoir cap, and
then add coolant or distilled water to raise
it to the specified level.
CAUTION:
Hard water or salt water is harmful to the en-
gine. You may use soft water if you can’t get
distilled water.
NOTE:
If water is added, have a Yamaha dealer
check the antifreeze content of the coolant
as soon as possible.
The radiator fan operation is completely au-
tomatic. It is switched on or off according to
the coolant temperature in the radiator.
If your ATV overheats, see page 8-120 for details.Coolant reservoir capacity:
0.29 L
1. Coolant reservoir cap
2. Maximum level mark
3. Minimum level mark
1. Cache du vase d’expansion
2. Repère de niveau maximum
3. Repère de niveau minimum
1. Tapa del depósito de líquido refrigerante
2. Marca de nivel máximo
3. Marca de nivel mínimo

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CAUTION:
Hard water or salt water is harmful to the en-
gine. You may use soft water if you cannot get
distilled water.
11. Install the radiator cap.
12. Start the engine and let it idle for several
minutes. Stop the engine, and then check
the coolant level in the radiator. If it is low,
add more coolant until it reaches the top
of the radiator.
13. Fill the coolant reservoir with coolant up
to the maximum level.
14. Install the coolant reservoir cap and check
for coolant leakage.
NOTE:
If any leakage is found, have a Yamaha dealer
check the cooling system.
15. Install the panel.

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1. Check hose
1. Flexible de contrôle
1. Manguito de comprobación
1. Air filter case cover 2. Holder (× 6)
1. Couvercle du boîtier de filtre à air 2. Support (× 6)
1. Tapa de la caja del filtro 2. Soporte (× 6)
EBU00818
Air filter element cleaning
NOTE:
There is a check hose at the bottom of the air
filter case. If dust or water collects in this hose,
empty the hose and clean the air filter element
and air filter case.
1. Remove the seat. (See page 8-15 for seat
removal procedure.)
2. Remove the air filter case cover by un-
hooking the holders.
3. Remove the air filter element and remove
it from its frame.
4. Wash the element gently but thoroughly
in solvent.
WARNING
Always use parts cleaning solvent to clean the
air filter element. Never use low flash point sol-
vents or gasoline to clean the air filter element
because the engine could catch fire or explode.