2004 YAMAHA YFM660R radiator

5-19
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. _
EBU00498
Chain
Check the general condition of the chain and
check the chain slack before every ride. Lubricate
and adjust the chain as necessary. (See pages
8-83–8-89 for details.)
U5LP63.book Page 19 Monday, March 10, 2003 2:06 PM

8-35
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 8-126 for details.
U5LP63.book Page 35 Monday, March 10, 2003 2:06 PM

8-37 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
EBU10241
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 under
pressure. Always put a thick rag over the cap
when opening. Allow any remaining pressure
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.
U5LP63.book Page 37 Monday, March 10, 2003 2:06 PM

8-43
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.
U5LP63.book Page 43 Monday, March 10, 2003 2:06 PM

8-126
Engine overheatingNOTE: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.
U5LP63.book Page 126 Monday, March 10, 2003 2:06 PM

10-3
Radiator capacity (including all routes) 1.3 L
Air filter Wet element
Fuel:
Type
Tank capacity
Reserve amountUnleaded gasoline only
For Europe: Regular unleaded gasoline only with a
research octane number of 91 or higher
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
U5LP63.book Page 3 Monday, March 10, 2003 2:06 PM