2001 YAMAHA YFM660R radiator cap

5-19
Yuki_DATA2:HM00G210_YFM660R-60:YFM350-5.frameEL
WARNING
Wait for the engine and radiator to cool before
removing the radiator cap. You could be
burned by hot fluid and steam blown out un-
der pressure. Always put a thick rag over the
cap when opening. Allow any remaining pres-
sure to escape before completely removing
the cap.
EBU00498
Chain
Check the general condition of the chain and
check the chain slack before every ride. Lubri-
cate and adjust the chain as necessary. (See
pages 8-77 ~ 8-83 for details.)

8-31
Yuki_DATA2:HM00G210_YFM660R-60:YFM350-8.frameEL
EBU00783
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

8-33
Yuki_DATA2:HM00G210_YFM660R-60:YFM350-8.frameEL
EBU00817
Changing the coolant
WARNING
Wait for the engine and radiator to cool before
removing the radiator cap. You could be
burned by hot fluid and steam blown out un-
der pressure. Always put a thick rag over the
cap when opening. Allow any remaining pres-
sure to escape before completely removing
the cap.
1. Place the ATV on a level surface.
2. Remove panel A. (See page 8-15 for panel
removal and installation procedures.)
3. Place a container under the engine, and
then remove the coolant drain bolt.
4. Remove the radiator cap.
5. Remove the coolant reservoir cap.
1. Coolant drain bolt
1. Boulon de vidange du liquide de refroidissement
1. Perno de drenaje de refrigerante
1. Radiator cap
1. Bouchon de radiateur
1. Tapa del radiador

8-39
Yuki_DATA2:HM00G210_YFM660R-60:YFM350-8.frameEL
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.

8-120
Yuki_DATA2:HM00G210_YFM660R-60:YFM350-8.frameER
Engine overheating
NOTE:
If it is difficult to get the recommended coolant, tap water can be temporarily used, provided that it
is changed to the recommended coolant as soon as possible.
WARNING
Wait for the engine and radiator to cool before removing the radiator cap. You could be burned by
hot fluid and steam blown out under pressure. Always put a thick rag over the cap when opening.
Allow any remaining pressure to escape before completely removing the cap.
Wait until the
engine has cooled.Check the coolant level in the
reservoir tank and/or radiator.
Level is OK.
Level is low, check the
cooling system for leakage.
No
leakage.
Leakage.Ask a Yamaha dealer to inspect
and repair the cooling system.
Add coolant. (See NOTE.)
Restart the engine. If the engine overheats again, ask a
Yamaha dealer to inspect and/or repair the cooling system.

Yuki_DATA2:HM00G210_YFM660R-60:YFM350-SPEC-E.frameEL
10-3
Radiator capacity (including all routes): 1.3 L
Air filter: Wet type element
Fuel:
Type
Tank capacity
Reserve amountRegular unleaded gasoline
12 L
2.6 L
Carburetor:
Type
× quantity
ManufacturerBSR33
× 2
MIKUNI
Spark plug:
Type/manufacturer
GapDPR8EA-9/NGK
0.8 ~ 0.9 mm
Clutch:
Type
OperationWet, Multiple-disc
Left hand operation
Transmission:
Primary Reduction System
Primary Reduction Ratio
Secondary Reduction System
Secondary Reduction Ratio
Transmission type
OperationSpur gear
71/34 (2.088)
Chain drive
40/13 (3.076)
Constant mesh, 5-speed forward, 1-speed reverse
Left foot operation MODEL YFM660R