2004 YAMAHA YZF-R1S Service Manual

4-46
FRONT FORKCHAS
Order Job / Part Q’ty Remarks
Washer
Damper rod assembly bolt
Copper washer
Damper rod assembly
Inner tube
Outer tube1
1
1
1
1
1
For assembly, reverse the disassembly
procedure.
11
12
13
14
15
16
23 Nm (2.3 m
kg, 17 ft
lb)
15 Nm (1.5 m
kg, 11 ft
lb)
23 Nm (2.3 m
kg, 17 ft
lb)
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4-47
FRONT FORKCHAS
WARNING
NOTE:
WARNING
EAS00649
REMOVING THE FRONT FORK LEGS
The following procedure applies to both of the
front fork legs.
1. Stand the motorcycle on a level surface.
Securely support the motorcycle so that
there is no danger of it falling over.
Place the motorcycle on a suitable stand so that
the front wheel is elevated.
2. Remove

front wheel

front brake caliper
Refer to “FRONT WHEEL AND BRAKE
DISCS”.
3. Remove:

Side Cowlings
Refer to “COWLINGS” in chapter 3.

handlebar
4. Loosen:

handlebar pinch bolt
1

upper bracket pinch bolt 2

cap bolt 3

under bracket pinch bolt 4
Before loosening the upper and under
bracket pinch bolts, support the front fork
leg.
5. Remove:

front fork leg
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4-48
FRONT FORKCHAS
NOTE:
WARNING
NOTE:
CAUTION:
EAS00652
DISASSEMBLING THE FRONT FORK LEGS
The following procedure applies to both of the
front fork legs.
1. Remove:

cap bolt
1
(from the damper adjusting rod)

spacer
2

nut 3
a. Press down on the spacer with the fork
spring compressor
4.
b. Install the rod holder
5 between the nut 3
and the spacer 2.
Fork spring compressor
90890-01441, YM-01441
Rod holder
90890-01434, YM-01434
Use the side of the rod holder that is marked “B”.
c. Loosen the nut.
d. Remove the cap bolt.
e. Remove the rod holder and fork spring com-
pressor.
The fork spring is compressed.
f. Remove the spacer and nut.
2. Drain:

fork oil
Stroke the damper rod
1 several times while
draining the fork oil.
3. Remove:

dust seal

oil seal clip
1

oil seal

washer
(with a flat-head screwdriver)
Do not scratch the inner tube.
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4-49
FRONT FORKCHAS
NOTE:
WARNING
4. Remove:

damper rod assembly bolt

damper rod assembly
While holding the damper rod assembly with the
damper rod holder
1, loosen the damper rod
assembly bolt.
Damper rod holder
90890-01423, YM-01423
EAS00656
CHECKING THE FRONT FORK LEGS
The following procedure applies to both of the
front fork legs.
1. Check:

inner tube
1

outer tube 2
Bends / damage / scratches
Replace.
Do not attempt to straighten a bent inner
tube as this may dangerously weaken it.
2. Measure:

spring free length
a
Out of specification
Replace.
Spring free length
236.5 mm (9.31 in)
: 231.8 mm (9.13 in)
3. Check:

damper rod
1
Damage / wear
Replace.
Obstruction
Blow out all of the oil pas-
sages with compressed air.

damper rod adjusting rod
Bends / damage
Replace.
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4-50
FRONT FORKCHAS
CAUTION:
WARNING
NOTE:
The front fork leg has a built-in damper ad-
justing rod and a very sophisticated inter-
nal construction, which are particularly
sensitive to foreign material.

When disassembling and assembling the
front fork leg, do not allow any foreign ma-
terial to enter the front fork.
4. Check:

cap bolt O-ring
1
Damage / wear
Replace.
EAS00659
ASSEMBLING THE FRONT FORK LEGS
The following procedure applies to both of the
front fork legs.

Make sure the oil levels in both front fork
legs are equal.

Uneven oil levels can result in poor han-
dling and a loss of stability.

When assembling the front fork leg, be sure to
replace the following parts:
– outer tube bushing
– oil seal
– dust seal
– Before assembling the front fork leg, make
sure all of the components are clean.
1. Install:

inner tube
1

damper rod assembly 2

damper rod assembly bolt

copper washer
New
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4-51
FRONT FORKCHAS
WARNING
CAUTION:
23 Nm (2.3 m
kg, 17 ft
lb)
NOTE:
Always use new copper washer.
Allow the damper rod assembly to slide
slowly down the inner tube
1 until it pro-
trudes from the bottom of the inner tube. Be
careful not to damage the inner tube.
2. Lubricate:

inner tube’s outer surface
Recommended lubricant
Suspension oil “01” or
equivalent
3. Tighten:

damper rod assembly bolt
1
LOCTITE
While holding the damper rod assembly with the
damper rod holder
2, tighten the damper rod
assembly bolt.
Damper rod holder
90890-01423, YM-01423
4. Install:

dust seal
1

oil seal clip 2

oil seal 3

washer 4
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4-52
FRONT FORKCHAS
CAUTION:
NOTE:
NOTE:
Make sure the numbered side of the oil seal
faces up.

Before installing the oil seal, lubricate its lips
with lithium-soap-based grease.

Lubricate the outer surface of the inner tube
with fork oil.

Before installing the oil seal, cover the top of
the front fork leg with a plastic bag to protect
the oil seal during installation.
5. Install :

Oil seal
1
(with the fork seal driver 2)
Fork seal driver
90890-01442, YM-01442
6. Install:

oil seal clip
1
Adjust the oil seal clip so that it fits into the outer
tube’s groove.
7. Install:

dust seal
1
(with the fork seal driver weight 2)
Fork seal driver
90890-01442m YM-01442
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4-53
FRONT FORKCHAS
NOTE:
NOTE: 8. Install:

rod puller
1

rod puller attachment 2
(onto the damper rod 3)
Rod puller
90890-01437, YM-01437
Rod puller attachment
90890-01436, YM-01436
9. Fill:

front fork leg
(with the specified amount of the recom-
mended fork oil)
Quantity (each front fork leg)
0.53 L (0.47 Imp qt, 0.56 US qt)
Recommended oil
Suspension oil “01” or
equivalent
Front fork leg oil level (from the
top of the outer tube, with the
outer tube fully compressed and
without the fork spring)
76 mm (2.99 in)

While filling the front fork leg, keep it upright.

After filling, slowly pump the front fork leg up
and down to distribute the fork oil.
10. Install:

nut
1

fork spring 2

spacer 3

damper adjusting rod 4

cap bolt 5
a. Remove the rod puller and adapter.
b. Install the nut.
c. Install the fork spring, and spacer.
Install the spring with the smaller pitch
a facing
up
A.
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