Yamaha YFM660 01 User Manual

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ADJUSTING THE REAR SHOCK 
ABSORBER
1.Adjust:

Spring preload
***********************************************
Adjustment steps:

Elevate the rear wheels by placing a suitable
stand under the frame.

Loosen the locknut 1
.

Turn the adjusting ring 2
 in direction a
 or
b
.
NOTE:

Be sure to remove all dirt and mud from
around the locknut and adjusting ring before
adjustment.

The length of the spring (installed) changes
1.5 mm (0.06 in) per turn of the adjuster.
CAUTION:
Never attempt to turn the adjusting ring
beyond the maximum or minimum setting.

Tighten the locknut 1
.
NOTE:
Always tighten the locknut against the adjust-
ing ring, then torque it to specification.
***********************************************
Direction a Spring preload is 
increased (suspension 
is harder).
Direction b Spring preload is 
decreased (suspension 
is softer).
Adjusting length c:
Standard: 253 mm (9.96 in)
Minimum: 245 mm (9.65 in)
Maximum: 260 mm (10.24 in)
T R..
Locknut:
42 Nm (4.2 m  kg, 30 ft  lb)
ADJUSTING THE REAR SHOCK ABSORBER 
						

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2.Adjust:

Rebound damping force
***********************************************
Adjustment steps:

Turn the adjusting screw 1
 in direction a
 or
b
.
CAUTION:
Do not force the adjuster past the minimum
or maximum extent of adjustment. The
adjuster may be damaged.
***********************************************
Direction a Rebound damping force 
is increased.
Direction b Rebound damping force 
is decreased.
From the fully turned-in position:
Standard: 10 clicks out
Minimum: 20 clicks out
Maximum: 3 clicks out
3.Adjust:

Compression damping force
***********************************************
Adjustment steps:

Turn the adjusting screw 1
 in direction a
 or
b
.
Direction a Compression damping 
force is increased.
Direction b Compression damping 
force is decreased.
From the fully turned-out position:
Standard: 7 clicks in
Minimum: 1 click in
Maximum: 12 clicks in
ADJUSTING THE REAR SHOCK ABSORBER 
						

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ADJADJUSTING THE REAR SHOCK ABSORBER/
CHECKING THE TIRE
CAUTION:
Do not forc the adjuster past the minimum
or maximum extent of adjustment. The
adjuster may be damaged.
***********************************************
CHECKING THE TIRE
WARNING
This model is equipped with low pressure
tires. It is important that they be inflated cor-
rectly and maintained at the proper pressures.

TIRE CHARACTERISTICS
1)Tire characteristics influence the handling
of ATV’s. The tires listed below have been
approved by Yamaha Motor Co., Ltd. for
this model. If other tire combinations are
used, they can adversely affect your
machine’s handling characteristics and
are therefore not recommended.

TIRE PRESSURE
1)Recommended tire pressure
Front 27.5 kPa (0.275 kg/cm
2, 4.0 psi)
Rear 27.5 kPa (0.275 kg/cm
2, 4.0 psi)
2)Tire pressure below the minimum specifi-
cation could cause the tire to dislodge
from the rim under severe riding condi-
tions.
The following are minimums:
Front 24.5 kPa (0.245 kg/cm
2, 3.5 psi)
Rear 24.5 kPa (0.245 kg/cm
2, 3.5 psi)
3)Use no more than
Front 250 kPa (2.5 kg/cm
2, 36 psi)
Rear 250 kPa (2.5 kg/cm
2, 36 psi)
when seating the tire beads. Higher pres-
sures may cause the tire to burst.
Inflate the tires slowly and carefully.
Fast inflation could cause the tire to
burst.Manufacturer Size Type
Front DUNLOP AT21×7-10KT311 
Radial
Rear DUNLOP AT20×10-9KT335 
Radial 
						

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CHECKING THE TIRE

MAXIMUM LOADING LIMIT
1)Vehicle load limit (total weight of cargo, 
rider and accessories, and tongue 
weight): 100 kg (220 lb)
1.Measure:

Tire pressure (cold tire pressure)
Out of specification →
 Adjust.
NOTE:

The low-pressure tire gauge 1
 is included
as standard equipment.

If dust or the like is stuck to this gauge, it will
not provide the correct readings. Therefore,
take two measurements of the tire’s pressure
and use the second reading.
WARNING
Uneven or improper tire pressure may
adversely affect the handling of this
machine and may cause loss of control.

Maintain proper tire pressures.

Set tire pressures when the tires are cold.

Tire pressures must be equal in both front
tires and equal in both rear tires.
Cold tire 
pressureFront Rear
Standard27.5 kPa
(0.275 kg/cm
2,
4.0 psi)27.5 kPa
(0.275 kg/cm2,
4.0 psi)
Minimum24.5 kPa
(0.245 kg/cm
2,
3.5 psi)24.5 kPa
(0.245 kg/cm2,
3.5 psi)
Maximum30.5 kPa
(0.305 kg/cm
2,
4.4 psi)30.5 kPa
(0.305 kg/cm2,
4.4 psi) 
						

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ADJCHECKING THE TIRE/CHECKING THE WHEEL/
CHECKING AND LUBRICATING THE CABLE
2.Check:

Tire surfaces
Wear/damage →
 Replace.
WARNING
It is dangerous to ride with a worn-out tire.
When tire wear is out of specification,
replace the tire immediately.
Tire wear limit a:
Front and rear: 3.0 mm (0.12 in)
CHECKING THE WHEEL
1.Check:

Wheels 1
 
Damage/bends →
 Replace.
NOTE:
Always balance the wheel when a tire or wheel
has been changed or replaced.
WARNING

Never attempt even small repairs to the
wheel.

Ride conservatively after installing a tire
to allow it to seat itself properly on the
rim.
CHECKING AND LUBRICATING THE 
CABLE
WARNING
A damaged cable sheath may cause corro-
sion and interfere with the cable move-
ment. An unsafe condition may result so
replace a damaged cable as soon as possi-
ble. 
						

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ADJCHECKING AND LUBRICATING THE CABLE/
LUBRICATING THE LEVERS AND PEDAL
1.Check:

Cable sheath 
Damage →
 Replace.
2.Check:

Cable operation
Unsmooth operation →
 Lubricate or replace.
NOTE:
Hold the cable end up and apply several drops
of lubricant to the cable.
3.Apply:

Lithium soap base grease
(onto end of the cable)
Recommended lubricant:
Yamaha chain and cable lube or
Engine oil
LUBRICATING THE LEVERS AND PEDAL
1.Lubricate the pivoting parts.
Recommended lubricant:
Lithium soap base grease 
						

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CHECKING THE BATTERY
EB305000
ELECTRICAL
CHECKING THE BATTERY
NOTE:
Since the MF battery is a sealed type battery, it
is not possible to measure the specific gravity
of the electrolyte in order to check the charge
state of the battery. Therefore the charge of
the battery has to be checked by measuring
the voltage at the battery terminals.
CAUTION:
CHARGING METHOD

This is a sealed type battery. Never
remove the sealing caps. If the sealing
caps have been removed, the balance will
not be maintained and battery perfor-
mance will deteriorate.

Charging time, charging current and
charging voltage for the MF battery are
different from those of general type bat-
teries. The MF battery should be charged
as explained in “CHARGING METHOD”. If
the battery is overcharged, the electrolyte
level will drop considerably. Therefore,
take special care when charging the bat-
tery.
WARNING
Battery electrolyte is dangerous; it con-
tains sulfuric acid which is poisonous and
highly caustic.
Always follow these preventive measures:

Avoid bodily contact with electrolyte as it
can cause severe burns or permanent eye
injury.

Wear protective eye gear when handling
or working near batteries.
Antidote (EXTERNAL):

SKIN - Wash with water.

EYES - Flush with water for 15 minutes
and get immediate medical attention.
Antidote (INTERNAL):

Drink large quantities of water or milk fol-
lowed with milk of magnesia, beaten egg
or vegetable oil. Get immediate medical
attention. 
						

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CHECKING THE BATTERY
Batteries generate explosive hydrogen gas.
Always follow these preventive measures:

Charge batteries in a well-ventilated area.

Keep batteries away from fire, sparks or
open flames (e.g., welding equipment,
lighted cigarettes, etc.).

DO NOT SMOKE when charging or han-
dling batteries.
KEEP BATTERIES AND ELECTROLYTE
OUT OF REACH OF CHILDREN.
1.Remove:

Seat

Battery holding bracket
Refer to “SEAT, FENDERS AND FUEL
TANK”.
2.Disconnect:

Battery leads
CAUTION:
First disconnect the negative lead 1, then
disconnect the positive lead 2.
3.Remove:

Battery
4.Check:

Battery condition
***********************************************
Battery condition checking steps:

Connect a digital voltmeter to the battery ter-
minals.
NOTE:
The charge state of an MF battery can be
checked by measuring the open-circuit voltage
(i.e. the voltage when the positive terminal is
disconnected).Tester (+) lead → battery (+) terminal
Tester (–) lead → battery (–) terminal
Open-circuit
voltageCharging time
12.8 V or higherNo charging is
necessary. 
						

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Check the condition of the battery using the
following charts.
Example:

Open-circuit voltage = 12.0 V

Charging time = 6.5 hours

Charge condition of the battery = 20 ~ 30%

Charging method for MF batteries
CAUTION:

If it is impossible to set the standard
charging current, be careful not to over-
charge.

When charging the battery, be sure to
remove it from the motorcycle. (If charg-
ing has to be done with the battery
mounted on the motorcycle, be sure to
disconnect the wire at the negative termi-
nal.)

Never remove the sealing caps of an MF
battery.

Make sure that the charging clips are in
full contact with the terminal and that they
are not shorted together. (A corroded clip
on the charger may cause the battery to
generate heat in the contact area. A weak
clip spring may cause sparks.)

Before removing the clips from the bat-
tery terminals, be sure to turn off the
charger’s power switch.

The open-circuit voltage variation for the
MF battery, after charging, is shown
below. As shown in the figure, the open-
circuit voltage stabilizes about 30 min-
utes after charging has been completed.
Therefore, wait 30 minutes after charging
is completed before measuring the open-
circuit voltage.
***********************************************
CHECKING THE BATTERY 
						

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CHECKING THE BATTERY
Charging method using a variable voltage charger