2001 YAMAHA YFM660R fuel

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Starting a cold engine
WARNING
Always make sure all control cables work
smoothly before you begin riding in cold
weather. If the control cables are frozen or do
not work smoothly, you could be unable to
control the ATV, which could lead to an acci-
dent or collision.
1. Set the parking brake.
2. Turn the fuel cock to “ON”.
3. Turn the main switch to “ON” and the en-
gine stop switch to “ ”.
4. Shift the transmission into neutral.

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Parking
When parking, stop the engine and shift into
neutral. Turn the fuel cock to “OFF” and apply
the parking brake.
1. Button 2. Lock plate
1. Bouton 2. Verrou
1. Botón 2. Placa de bloqueo
1. Lock position
1. Position de verrouillage
1. Posición de bloqueo

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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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Valve clearance adjustment
The correct valve clearance changes with use,
resulting in improper fuel/air supply or engine
noise. To prevent this, the valve clearance
must be adjusted regularly. This adjustment
however, should be left to a professional
Yamaha service technician.
EBU00306
Reverse lock release cable adjustment
The reverse lock release cable stretches with
use, resulting in improper function. To prevent
this, the cable must be adjusted regularly. This
adjustment, however, should be left to a
Yamaha dealer.

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Troubleshooting
Although Yamaha machines receive a rigid in-
spection before shipment from the factory,
trouble may occur during operation.
Any problem in the fuel, compression, or igni-
tion systems can cause poor starting and loss
of power. The troubleshooting chart describes
a quick, easy procedure for making checks. If
your machine requires any repair, take it to a
Yamaha dealer.
The skilled technicians at a Yamaha dealership
have the tools, experience, and know-how to
properly service your machine. Use only genu-
ine Yamaha parts on your machine. Imitation
parts may look like Yamaha parts, but they are
often inferior. Consequently, they have a short-
er service life and can lead to expensive repair
bills.
WARNING
Do not smoke when checking the fuel system.
Fuel can ignite or explode, causing severe inju-
ry or property damage. Make sure there are no
open flames or sparks in the area, including pi-
lot lights from water heaters or furnaces.

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Troubleshooting chart
Starting problems or poor engine performance
1. Fuel
Check if there is fuel
in the fuel tank.There is fuel.Turn the fuel cock
lever to “OFF”.No fuel.Fuel cock is
clogged.
Clean the
fuel cock. Some fuel.Turn the fuel cock
lever to “RES”.Restart the engine.
No fuel.Supply fuel.
2. Compression
Use the electric
starter to see if
there is compression.There is compression.
Compression normal.
No compression.Ask a Yamaha dealer to
inspect.
3. Ignition
Remove the
spark plug and
check electrodes.WetWipe clean with dry cloth.
DryAttach spark plug cap and
ground to chassis.Use the
electric starter.Spark is good.Ignition system is
normal.
Spark is weak.
Adjust the spark plug gap
or replace the spark plug. No spark.
Ask a Yamaha dealer to
inspect. 4. Battery
Use the electric starter.Engine turns over
quickly.Battery is good.
Engine turns over
slowly.Check the connections.Check the
fuel flow.
Turn the fuel cock
lever to “ON”.
Remove the fuel hose
from the fuel cock.

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B. STORAGE
Long term storage (60 days or more) of your
machine will require some preventive proce-
dures to guard against deterioration. After
thoroughly cleaning the machine, prepare for
storage as follows:
1. Fill the fuel tank with fresh fuel and add
fuel stabilizer (if available).
NOTE:
Use of fuel stabilizer eliminates the need to
drain the fuel system. Consult a Yamaha dealer
if the fuel system is to be drained instead.
2. Remove the spark plug, pour about one
tablespoon of SAE 10W30 or 20W40 mo-
tor oil in the spark plug hole and reinstall
the spark plug. Ground the spark plug
wire and turn the engine over several
times to coat the cylinder wall with oil.
3. Clean the drive chain thoroughly and lu-
bricate it. (See page 8-81.)
4. Lubricate all control cables.

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SPECIFICATIONS
MODEL YFM660R
Dimension:
Overall length
Overall width
Overall height
Seat height
Wheel base
Ground clearance
Minimum turning radius1,830 mm
1,100 mm
1,150 mm
860 mm
1,245 mm
265 mm
3,300 mm
Basic weight:
With oil and full fuel tank 193 kg
Engine:
Type
Cylinder arrangement
Displacement
Bore× Stroke
Compression ratio
Starting system
Lubrication systemLiquid-cooled, 4-stroke, SOHC
Single cylinder, forward inclined
660 cm
3
100
× 84 mm
9.2 : 1
Electric starter
Dry sump