2002 YAMAHA YFM660R check engine

5-21
EBU00151
Throttle lever
Check to see that the throttle lever operates cor-
rectly. It must open smoothly and spring back to
idle position when released. Repair as necessary
for proper operation.
EBU00152
Fittings and Fasteners
Always check the tightness of chassis fittings and
fasteners before a ride. Take the machine to a
Yamaha dealer or refer to the Service Manual for
correct tightening torque.
EBU00991
Lights
Check the headlights and tail/brake light to make
sure they are in working condition. Repair as nec-
essary for proper operation.
EBU00912
Switches
Check the operation of the light switch, engine
stop switch and any other switches. Repair as nec-
essary for proper operation.
U5LP61.book Page 21 Monday, August 27, 2001 3:49 PM

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.
U5LP61.book Page 9 Monday, August 27, 2001 3:49 PM

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.)
Carburetors*•Check starter (choke) operation.
•Adjust engine idling speed and synchronization.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.U5LP61.book Page 7 Monday, August 27, 2001 3:49 PM

8-17 1. Engine oil tank
2. Engine oil tank 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 del depósito de aceite de motor
3. Marca de nivel máximo
4. Marca de nivel mínimo
EBU01014
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 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 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.
U5LP61.book Page 17 Monday, August 27, 2001 3:49 PM

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. _
U5LP61.book Page 23 Monday, August 27, 2001 3:49 PM

8-29
12. Start the engine, and then let it idle for sever-
al minutes while checking it for oil leakage. If
oil is leaking, immediately turn the engine off
and check for the cause.
13. Turn the engine off, and then check the oil
level and correct it if necessary.
U5LP61.book Page 29 Monday, August 27, 2001 3:49 PM

8-31 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 8-122 for details.Coolant reservoir capacity:
0.29 L
U5LP61.book Page 31 Monday, August 27, 2001 3:49 PM

8-39
CAUTION:_ Hard water or salt water is harmful to the en-
gine. You may use soft water if you cannot get
distilled water. _12. Install the radiator cap and the coolant reser-
voir cap.
13. Start the engine and let it idle for several min-
utes. 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 ra-
diator.
14. Check the coolant level in the reservoir. If it is
low, add coolant to the maximum level mark.
15. Start the engine and then check for coolant
leakage.NOTE:_ If any leakage is found, have a Yamaha dealer
check the cooling system. _16. Install the panel.
U5LP61.book Page 39 Monday, August 27, 2001 3:49 PM