length YAMAHA YZ85 2004 User Guide

4 - 28
ENG
REMOVAL POINTS
Clutch boss
1. Remove:

Nut (clutch boss) 1

Conical washer 2

Clutch boss 3
NOTE:
Use the clutch holding tool 4 to hold the clutch
boss.
ÈFor USA and CDN
ÉExcept for USA and CDN
Clutch holding tool:
YM-91042/90890-04086
5PA40740
ÈÉ
5PA40750
EC494000
INSPECTION
EC484100
Clutch housing and boss
1. Inspect:

Clutch housing 1
Cracks/wear/damage → Replace.

Clutch boss 2
Scoring/wear/damage → Replace.
5PA40760
EC484201
Primary driven gear
1. Check:

Circumferential play
Free play exists → Replace.

Gear teeth
a
Wear/damage → Replace.
5PA40770
Clutch spring
1. Measure:

Clutch spring free length
a
Out of limit → Replace springs as a set.
Clutch spring free length:
34.0 mm (1.34 in)
: 32.0 mm (1.26 in)
5PA40780
CLUTCH AND PRIMARY DRIVEN GEAR

5 - 31
CHAS
EC554200
Base valve
1. Inspect:

Valve assembly 1
Wear/damage → Replace.

O-ring 2
Damage → Replace.
5PA50900
EC554400
Fork spring
1. Measure:

Fork spring free length a
Out of specification → Replace.
EC554502
Inner tube
1. Inspect:

Inner tube surface a
Score marks → Repair or replace.
Use #1,000 grit wet sandpaper.
Damaged oil lock piece → Replace.

Inner tube bends
Out of specification → Replace.
Use the dial gauge 1.
NOTE:
The bending value is shown by one half of the
dial gauge reading.
WARNING
Do not attempt to straighten a bent inner
tube as this may dangerously weaken the
tube.
EC554600
Outer tube
1. Inspect:

Outer tube 1
Score marks/wear/damage → Replace.
Fork spring free length:
430 mm (16.9 in)
: 425 mm (16.7 in)
Inner tube bending limit:
0.2 mm (0.008 in)
5PA50910
5PA50920
5PA50930
FRONT FORK

5 - 61
CHAS
3. Adjust:

Spring length (installed) a
* For EUROPE
NOTE:
The length of the spring (installed) changes
1.5 mm (0.06 in) per turn of the adjuster.
CAUTION:
Never attempt to turn the adjuster beyond
the maximum or minimum setting.
4. Tighten:

Locknut 1
Spring length (installed) a:
YZ85: 215 mm (8.46 in)
*212 mm (8.35 in)
YZ85LW: 207 mm (8.15 in)
*212 mm (8.35 in)
Extent of adjustment
202.5 ~ 218.5 mm
(7.97 ~ 8.60 in)
5PA51920
5PA51930
Rear shock absorber
1. Install:

Rear shock absorber
2. Install:

Bolt (rear shock absorber-frame) 1

Washer 2

Nut (rear shock absorber-frame) 3
NOTE:
Apply the molybdenum disulfide grease on the
bolt.
3. Install:

Washer 1

Bolt (rear shock absorber-relay arm) 2
NOTE:

Apply the molybdenum disulfide grease on
the bolt.

Insert the bolt from left side.
5PA51940
T R..36 Nm (3.6 m · kg, 25 ft · lb)
5PA51950
T R..36 Nm (3.6 m · kg, 25 ft · lb)
REAR SHOCK ABSORBER

7 - 14
TUN
Front fork setting parts

Front fork spring 1
YZ85
YZ85LW
NOTE:
The I.D. mark (slits) a is proved on the end of
the spring.TYPESPRING
RATESPRING
PART NUMBERI.D.
MARK
(slits)
SOFT 0.280 4ES-23141-50 I
STD 0.290 4ES-23141-40–
STIFF 0.300 4ES-23141-60 II
TYPESPRING
RATESPRING
PART NUMBERI.D.
MARK
(slits)
SOFT 0.290 4ES-23141-40–
STD 0.300 4LB-23141-10–
STIFF 0.310 4ES-23141-70 III
5PA70150
EC72B000
Rear suspension setting
The rear suspension setting should be made
depending on the rider’s feeling of an actual
run and the circuit conditions.
The rear suspension setting includes the fol-
lowing two factors:
1. Setting of spring preload

Change the set length of the spring.

Change the spring.
2. Setting of damping force

Change the rebound damping.

Change the compression damping.
SETTING

7 - 15
TUNSETTING
EC72C001
Choosing set length
1. Place a stand or block under the engine to
put the rear wheel above the floor, and
measure the length a between the rear
wheel axle center and the rear fender hold-
ing bolt.
5PA70160
2. Remove the stand or block from the engine
and with a rider astride the seat, measure
the sunken length b between the rear
wheel axle center and the rear fender hold-
ing bolt.
5PA70170
3. Loosen the locknut 1 and make adjust-
ment by turning the spring adjuster 2 to
achieve the standard figure from the sub-
traction of the length b from the length a.
Standard figure:
75 ~ 85 mm (3.0 ~ 3.3 in)
5PA70180
NOTE:

If the machine is new and after it is broken in,
the same set length of the spring may
change because of the initial fatigue, etc. of
the spring. Therefore, be sure to make re-
evaluation.

If the standard figure cannot be achieved by
adjusting the spring adjuster and changing
the spring set length, replace the spring with
an optional one and make re-adjustment.

7 - 16
TUN
Setting of spring after replacement
After replacement, be sure to adjust the spring
to the set length [sunken length 75 ~ 85 mm
(3.0 ~ 3.3 in)] and set it.
1. Use of soft spring

Set the soft spring for less rebound damp-
ing to compensate for its less spring load.
Run with the rebound damping adjuster
one or two clicks on the softer side and
readjust it to suit your preference.
2. Use of stiff spring

Set the soft spring for more rebound damp-
ing to compensate for its greater spring
load. Run with the rebound damping
adjuster one or two clicks on the stiffer side
and readjust it to suit your preference.
*Adjusting the rebound damping will be fol-
lowed more or less by a change in the com-
pression damping. For correction, turn the
compression damping adjuster on the
softer side.
CAUTION:
When using a rear shock absorber other
than currently installed, use the one whose
overall length a does not exceed the stan-
dard as it may result in faulty performance.
Never use one whose overall length is
greater than standard.
ÈCoverage of spring by weight
ÉRider weight
1Soft
2Standard
3Stiff
Length a of standard shock:
403.5 mm (15.89 in)
5PA70190
5PA70140
SETTING

7 - 18
TUNSETTING
Suspension setting

Front fork
NOTE:

If any of the following symptoms is experienced with the standard position as the base, make
resetting by reference to the adjustment procedure given in the same chart.

Before any change, set the rear shock absorber sunken length to the standard figure 75 ~ 85 mm
(3.0 ~ 3.3 in).
SymptomSection
Check Adjust
JumpLarge
gapMedium
gapSmall
gap
Stiff over entire range
{{{Compression damping
Oil level (oil amount)
SpringTurn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Decrease oil level by about 5 ~ 10 mm (0.2 ~ 0.4 in).
Replace with soft spring.
Unsmooth movement
over entire range{{{{Outer tube
Inner tube
Under bracket tightening
torqueCheck for any bends, dents, and other noticeable
scars, etc. If any, replace affected parts.
Retighten to specified torque.
Poor initial
movement{Rebound damping
Oil sealTurn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Apply grease in oil seal wall.
Soft over entire range,
bottoming out{{Compression damping
Oil level (oil amount)
SpringTurn adjuster clockwise (about 2 clicks) to increase
damping.
Increase oil level by about 5 ~ 10 mm (0.2 ~ 0.4 in).
Replace with stiff spring.
Stiff toward stroke end{Oil level (oil amount) Decrease oil level by about 5 mm (0.2 in).
Soft toward stroke end,
bottoming out{Oil level (oil amount) Increase oil level by about 5 mm (0.2 in).
Stiff initial movement{{{{Compression dampingTurn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Low front, tending to
lower front posture{{Compression damping
Rebound damping
Balance with rear end
Oil level (oil amount)Turn adjuster clockwise (about 2 clicks) to increase
damping.
Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Set sunken length for 80 ~ 85 mm (3.1 ~ 3.3 in) when
one passenger is astride seat (lower rear posture).
Increase oil level by about 5 mm (0.2 in).
“Obtrusive” front, tend-
ing to upper front pos-
ture{{Compression damping
Balance with rear end
Spring
Oil level (oil amount)Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Set sunken length for 75 ~ 80 mm (3.0 ~ 3.1 in) when
one passenger is astride seat (upper rear posture).
Replace with soft spring.
Decrease oil level by about 5 ~ 10 mm (0.2 ~ 0.4 in).

7 - 19
TUNSETTING

Rear shock absorber
NOTE:

If any of the following symptoms is experienced with the standard position as the base, make
resetting by reference to the adjustment procedure given in the same chart.

Adjust the damping in 2-click increments or decrements.
SymptomSection
Check Adjust
JumpLarge
gapMedium
gapSmall
gap
Stiff, tending to sink
{{Rebound damping
Spring set lengthTurn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Set sunken length for 75 ~ 80 mm (3.0 ~ 3.1 in)
when one passenger is astride seat.
Spongy and unstable{{Rebound damping
SpringTurn adjuster clockwise (about 2 clicks) to increase
damping.
Replace with stiff spring.
Heavy and dragging{{Rebound damping
SpringTurn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Replace with soft spring.
Poor road gripping{Rebound damping
Compression damping
Spring set length
SpringTurn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Turn adjuster clockwise (about 2 clicks) to increase
damping.
Set sunken length for 75 ~ 80 mm (3.0 ~ 3.1 in)
when one passenger is astride seat.
Replace with soft spring.
Bottoming out{{Compression damping
Spring set length
SpringTurn adjuster clockwise (about 2 clicks) to increase
damping.
Set sunken length for 75 ~ 80 mm (3.0 ~ 3.1 in)
when one passenger in astride seat.
Replace with stiff spring.
Bouncing{{Rebound damping
SpringTurn adjuster clockwise (about 2 clicks) to increase
damping.
Replace with soft spring.
Stiff travel{{Compression damping
Spring set length
SpringTurn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Set sunken length for 80 ~ 85 mm (3.1 ~ 3.3 in)
when one passenger is astride seat.
Replace with soft spring.