2003 YAMAHA YFM660R check engine

6-9
EBU00180
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 en-
gine 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 lever. Other-
wise, the engine will misfire, preventing normal op-
eration.
U5LP62.book Page 9 Wednesday, May 8, 2002 11:24 AM

8-7
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 starter (choke) operation.
•Adjust engine idling speed.Crankcase breather
system*•Check breather hose for cracks or damage.
•Replace if necessary.Exhaust system*•Check for leakage.
•Tighten 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.Front brake*•Check free play/operation/fluid leakage/
See NOTE Page 8-8.
•Correct if necessary.Rear brake*•Check operation/fluid leakage/See NOTE Page 8-8.
•Correct if necessary.Clutch*•Check operation.
•Adjust if necessary.U5LP62.book Page 7 Wednesday, May 8, 2002 11:24 AM

8-17 1. Engine oil tank
2. Engine oil tank filler cap
3. Dipstick
4. Maximum level mark
5. Minimum level mark
1. Réservoir d’huile de moteur
2. Bouchon de remplissage de l’huile de moteur
3. Jauge
4. Repère de niveau maximum
5. Repère de niveau minimum
1. Depósito de aceite de motor
2. Tapa de relleno del depósito de aceite de motor
3. Varilla de medición
4. Marca de nivel máximo
5. Marca de nivel mínimo
EBU01238
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 intervals
specified in the periodic maintenance and lubrica-
tion chart.
To check the engine oil level
1. Place the ATV on a level surface.
2. Start the engine, warm it up until the engine
oil has reached a normal temperature of
60°C, let it continue to idle for twenty to thirty
seconds. During this period, rev the engine
two or three times to approximately
3,000 r/min, 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. _
U5LP62.book Page 17 Wednesday, May 8, 2002 11:24 AM

8-19
3. Wait a few minutes until the oil settles, re-
move the engine oil tank filler cap, wipe the
dipstick clean with a clean rag, insert it back
into the filler hole (without screwing it in), and
then remove it again to check the oil level.NOTE:_ The engine oil should be between the minimum
and maximum level marks. _4. If the engine oil is below the minimum level
mark, add sufficient oil of the recommended
type to raise it to the correct level.NOTE:_ When adding oil, be careful not to overfill the en-
gine oil tank; the oil level rises faster starting from
the half-level-portion on the dipstick. _5. Insert the dipstick into the oil filler hole, and
then tighten the oil filler cap.
U5LP62.book Page 19 Wednesday, May 8, 2002 11:24 AM

8-23 1. Crankcase engine oil drain bolt
1. Boulon de vidange d’huile du carter
1. Perno de drenaje de aceite de motor del cárter
1. Engine oil tank drain bolt
1. Boulon de vidange du réservoir d’huile de moteur
1. Perno de drenaje del depósito aceite de motor
4. Remove the crankcase engine oil drain bolt.
5. Remove the engine oil tank filler cap and the
oil tank drain bolt.
6. Check the washers for damage, and replace
if necessary.NOTE:_ Skip steps 7–8 if the oil filter cartridge is not being
replaced. _
U5LP62.book Page 23 Wednesday, May 8, 2002 11:24 AM

8-27
11. Pour only 1.75 L of the specified amount of
recommended engine oil through the engine
oil tank filler hole, insert the dipstick, and then
tighten the oil tank filler cap.
12. Start the engine, rev it several times, and
then turn it off.
13. Remove the engine oil tank filler cap, and
then gradually fill the oil tank with the remain-
ing oil quantity while regularly checking the oil
level on the dipstick. Tightening torques:
Crankcase engine oil drain bolt:
30 Nm (3.0 m·kgf)
Engine oil tank drain bolt:
25 Nm (2.5 m·kgf)
U5LP62.book Page 27 Wednesday, May 8, 2002 11:24 AM

8-31
14. Start the engine, and then let it idle for seve-
ral minutes while checking it for oil leakage. If
oil is leaking, immediately turn the engine off
and check for the cause.
15. Turn the engine off, and then check the oil
level and correct it if necessary.
U5LP62.book Page 31 Wednesday, May 8, 2002 11:24 AM

8-33 1. Coolant reservoir cap
2. Maximum level mark
3. Minimum level mark
1. Bouchon 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
EBU01015
Cooling system
1. Check the coolant level in the coolant reser-
voir when the engine is cold as the coolant
level will vary with engine temperature. The
coolant level should be between the maxi-
mum and minimum marks.
2. If the level is low, remove the coolant reser-
voir cap, and then add coolant or distilled wa-
ter 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 auto-
matic. It is switched on or off according to the
coolant temperature in the radiator.
_If your ATV overheats, see page 8-124 for details.Coolant reservoir capacity:
0.29 L
U5LP62.book Page 33 Wednesday, May 8, 2002 11:24 AM