Yamaha YFM660 01 User Manual

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CHK
ADJADJUSTING THE PARKING BRAKE/
CHECKING THE BRAKE FLUID LEVEL
WARNING
After this adjustment is performed, lift the
rear wheels off the ground by placing a
block under the engine, and spin the rear
wheels to ensure there is no brake drag. If
any brake drag is noticed perform the
above steps again.
***********************************************
CHECKING THE BRAKE FLUID LEVEL
1.Place the machine on a level surface.
NOTE:
When inspecting the brake fluid level, make
sure that the top of the brake fluid reservoir top
is horizontal.
2.Check:

Brake fluid level
Fluid level is below the “LOWER” level line
1
 →
 Add the recommended brake fluid to
the proper level.
ÈFront brake
ÉRear brake
CAUTION:
Brake fluid may erode painted surfaces or
plastic parts. Always clean up spilled fluid
immediately.
WARNING

Use only the designated quality brake
fluid: Otherwise, the rubber seals may
deteriorate, causing leakage and poor
brake performance.

Refill with the same type of brake fluid:
Mixing fluids may result in a harmful
chemical reaction and lead to poor perfor-
mance.

Be careful that water does not enter the
master cylinder when refilling. Water will
significantly lower the boiling point of the
fluid and may result in a vapor lock.
Recommended brake fluid:
DOT 4
È
É 
						

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CHK
ADJCHECKING THE FRONT BRAKE PAD/
CHECKING THE REAR BRAKE PAD/
ADJUSTING THE REAR BRAKE LIGHT SWITCH
CHECKING THE FRONT BRAKE PAD
1.Remove:

Front wheels
2.Check:

Brake pad
Wear indicators 1
 almost in contact with the
brake disc →
 Replace the brake pads as a
set.
Refer to “FRONT AND REAR BRAKES” in
CHAPTER 4.
3.Operate the brake lever.
4.Install:

Front wheels
Brake pad wear limit a:
1 mm (0.04 in)
CHECKING THE REAR BRAKE PAD
1.Check:

Brake pad
Wear indicators 1
 almost in contact with the
brake disc →
 Replace the brake pads as a
set.
Refer to “FRONT AND REAR BRAKES” in
CHAPTER 4.
2.Operate the brake pedal.
Brake pad wear limit a:
1 mm (0.04 in)
ADJUSTING THE REAR BRAKE LIGHT 
SWITCH
NOTE:
The rear brake light switch is operated by
movement of the brake pedal.
The rear brake light switch is properly adjusted
when the brake light comes on just before the
braking effect starts. 
						

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CHK
ADJADJUSTING THE REAR BRAKE LIGHT SWITCH/
CHECKING THE BRAKE HOSE
1.Check:

Rear brake light operation timing 
Incorrect →
 Adjust.
2.Adjust:

Rear brake light operation timing
***********************************************

Hold the main body 1
 of the rear brake light
switch so that it does not rotate and turn the
adjusting nut 2
 in direction a
 or b
 until the
rear brake light comes on at the proper time.
***********************************************
Direction a Brake light comes on 
sooner.
Direction b Brake light comes on 
later.
CHECKING THE BRAKE HOSE
1.Remove:

Seat

Front fender 
Refer to “SEAT, FENDERS AND FUEL
TANK”.
2.Check:

Front brake hoses 1
 

Rear brake hoses 2
 
Cracks/wear/damage →
 Replace.
3.Check:

Brake hose clamp
Loosen →
 Tighten.
4.Hold the machine in an upright position and
apply the front or rear brake.
5.Check:

Brake hoses
Apply the brake lever several times.
Fluid leakage →
 Replace the hose.
Refer to “FRONT AND REAR BRAKE” in
CHAPTER 4. 
						

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CHK
ADJCHECKING THE BRAKE HOSE/
BLEEDING THE HYDRAULIC BRAKE SYSTEM
6.Install:

Front fender

Seat
Refer to “SEAT, FENDERS AND FUEL
TANK”.
BLEEDING THE HYDRAULIC BRAKE 
SYSTEM
WARNING
Bleed the brake system if:

The system has been disassembled.

A brake hose or brake pipe have been
loosened or removed.

The brake fluid has been very low.

The brake operation has been faulty.
A loss of braking performance may occur if
the brake system is not properly bled.
1.Bleed:

Brake system
***********************************************
Air bleeding steps:
a. Add the proper brake fluid to the reservoir.
b. Install the diaphragm. Be careful not to spill
any fluid or allow the reservoir to overflow.
c. Connect the clear plastic hose 1
 tightly to
the caliper bleed screw 2
. 
ÈFront
ÉRear
d. Place the other end of the hose into a con-
tainer.
e. Slowly apply the brake lever or pedal sev-
eral times.
f. Pull the lever in or push down on the pedal
and hold it.
g. Loosen the bleed screw and allow the lever
or pedal to travel towards its limit.
h. Tighten the bleed screw when the lever or
pedal limit has been reached, then release
the lever or pedal.
i. Repeat steps (e) to (h) until all the air bub-
bles have disappeared from the fluid.
È
É 
						

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CHK
ADJ
j. Tighten the bleed screw.
NOTE:
If bleeding is difficult, it may be necessary to
let the brake fluid settle for a few hours.
Repeat the bleeding procedure when the tiny
bubbles in the system have disappeared.
k. Add brake fluid to the proper level.
Refer to “CHECKING THE BRAKE FLUID
LEVEL”.
WARNING
Check the operation of the brake after
bleeding the brake system.
***********************************************
T R..
Bleed screw:
6 Nm (0.6 m  kg, 4.3 ft  lb)
ADJUSTING THE SHIFT PEDAL
1.Check:

Shift pedal height a
 
Out of specification →
 Adjust.
Shift pedal height:
22 mm (0.89 in)
2.Adjust:

Shift pedal height
***********************************************
Adjustment steps:

Loosen the locknuts 1
.

Turn the adjusting rod 2
 in direction a
 or b
until the specified shift pedal position
obtained.

Tighten the locknuts.
***********************************************
Direction a Shift pedal position is 
down.
Direction b Shift pedal position is 
up.
T R..
Locknut:
8 Nm (0.8 m  kg, 5.8 ft  lb)
BLEEDING THE HYDRAULIC BRAKE SYSTEM/
ADJUSTING THE SHIFT PEDAL 
						

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CHK
ADJADJUSTING THE REVERSE CONTROL CABLE/
ADJUSTING THE DRIVE CHAIN SLACK
ADJUSTING THE REVERSE CONTROL 
CABLE
1.Check:

Reverse knob free play a
 
Out of specification →
 Adjust.
Reverse knob free play:
0 mm (0 in)
2.Adjust:
***********************************************
Adjustment steps:

Pull the boots 1
 and 2
 off.

Loosen the locknut 3
.

Turn the adjusting nut 4
 until the reverse
control cable 5
 is taut or the length a
 is
135 mm (5.31 in).
NOTE:
Be sure to hold the reverse shift lever 6
 when
make this adjustment so that it does not move.

Tighten the locknut 3
.

Pull the boots 1
 and 2
 in.
***********************************************
ADJUSTING THE DRIVE CHAIN SLACK
NOTE:
The drive chain slack must be checked at the
tightest point on the chain.
CAUTION:
A drive chain that is too tight will overload
the engine and other vital parts, and one
that is too loose can skip and damage the
swingarm or cause an accident. Therefore,
keep the drive chain slack within the speci-
fied limits.
1.Elevate the rear wheels by placing the suit-
able stand under the frame.
2.Rotate the rear wheel several times and
check the drive chain to locate its tightest
point. 
						

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CHK
ADJ
ADJUSTING THE DRIVE CHAIN SLACK
3.Measure:

Drive chain slack a
 
Out of specification →
 Adjust.
Drive chain slack:
30 ~ 45 mm (1.18 ~ 1.77 in)
4.Adjust:

Drive chain slack
***********************************************
Adjustment steps:

Loosen the hub nuts 1
.

Loosen the locknuts 2
.

Turn both adjusting bolts 3
 in direction a
 or
b
 until the specified drive chain slack is
obtained.
NOTE:
To maintain the proper axle alignment, adjust
both sides evenly. (There are marks c
 on
each side of hub.)
CAUTION:
Excessive chain slack will overload the
engine and other vital parts; keep the slack
within the specified limits.

If the chain slack cannot be adjusted, replace
the sprockets and drive chain as a set.

Tighten the hub nuts and locknuts.
NOTE:
The chain should be cleaned and lubricated
after every use of the machine.
***********************************************
Direction a Drive chain slack is 
reduced.
Direction b Drive chain slack is 
increased.
T R..
Hub nut:
90 Nm (9.0 m  kg, 65 ft  lb)
Locknut (chain puller):
16 Nm (1.6 m  kg, 11 ft  lb) 
						

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CHK
ADJCHECKING THE STEERING SYSTEM/
ADJUSTING THE TOE-IN
CHECKING THE STEERING SYSTEM
1.Place the machine on a level surface.
2.Check:

Steering assembly bushings
Move the handlebar up and down, and/or
back and forth.
Excessive play →
 Replace the steering stem
bushings.
3.Check:

Tie-rod ends
Turn the handlebar to the left and/or right
until it stops completely, then move the han-
dlebar from the left to the right slightly. Tie-
rod end has any vertical play →
 Replace the
tie-rod end(s).
4.Raise the front end of the machine so that
there is no weight on the front wheels.
5.Check:

Ball joints and/or wheel bearings
Move the wheels laterally back and forth.
Excessive free play →
 Replace the front
arms (upper and lower) and/or wheel bear-
ings.
ADJUSTING THE TOE-IN
1.Place the machine on a level surface.
2.Measure:

Toe-in
Out of specification →
 Adjust.
Toe-in:
0 ~ 10 mm (0 ~ 0.39 in) 
						

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CHK
ADJ
***********************************************
Toe-in measurement steps:
NOTE:
Before measuring the toe-in, make sure that
the tire pressure is correct.

Mark both front tire tread centers.

Raise the front end of the machine so that
there is no weight on the front tires.

Face the handlebar straight ahead.

Measure the width È
 between the marks.

Rotate the front tires 180° until the marks are
exactly opposite one another.

Measure the width É
 between the marks.

Calculate the toe-in using the formula given
below.

If the toe-in is incorrect, adjust it.
Ê
Forward
***********************************************
3.Adjust:

Toe-in
WARNING

Be sure that both tie-rods are turned the
same amount. If not, the machine will drift
right or left even though the handlebar is
positioned straight. This may lead to mis-
handling and an accident.

After setting the toe-in to specification, run
the machine slowly for some distance with
both hands lightly holding the handlebar
and check that the handlebar responds cor-
rectly. If not, turn either the right or left tie-
rod within the toe-in specification.Toe-in = É – È
ADJUSTING THE TOE-IN 
						

							3 - 44
CHK
ADJ
***********************************************
Adjustment steps:

Mark both tie-rods ends.
This reference point will be needed during
adjustment.

Loosen the locknuts (tie-rod end) 1
 of both
tie-rods.

The same number of turns should be given
to both the right and left tie-rods 2
 until the
specified toe-in is obtained. This is to keep
the length of the rods the same.

Tighten the rod end locknuts of both tie rods.
NOTE:
Adjust the rod ends so that A and B are equal.
***********************************************
T R..
Locknut (rod end):
15 Nm (1.5 m  kg, 11 ft  lb)
ADJUSTING THE FRONT SHOCK 
ABSORBER
WARNING
Always adjust both front shock absorber
spring preload to the same setting. Uneven
adjustment can cause poor handling and
loss of stability.
1.Adjust:

Spring preload
Turn the adjuster 1
 in direction a
 or b
.
Direction a Spring preload is 
increased (suspension 
is harder).
Direction b Spring preload is 
decreased (suspension 
is softer).
Standard position: 3
Minimum position: 1
Maximum position: 5
ADJUSTING THE TOE-IN/
ADJUSTING THE FRONT SHOCK ABSORBER