2007 YAMAHA YZ125LC oil

5-30
CHASFRONT FORK
Base valve
1. Remove:
9Base valve 1
From damper assembly 2.
NOTE:
Hold the damper assembly with the cap bolt ring
wrench 3and use the cap bolt wrench 4to
remove the base valve.
EC554000
INSPECTIONEC554100
Damper assembly
1. Inspect:
9Damper assembly 1
Bend/DamageReplace.
9O-ring 2
Wear/DamageReplace.
cC
The front fork with a built-in piston rod has
a very sophisticated internal construction
and is particularly sensitive to foreign ma-
terial.
Use enough care not to allow any foreign
material to come in when the oil is re-
placed or when the front fork is disassem-
bled and reassembled.
Cap bolt wrench:
YM-01500/90890-01500
Cap bolt ring wrench:
YM-01501/90890-01501
1C3-9-32-5B 4/7/06 2:47 PM Page 10

5-32
CHASFRONT FORK
EC554502
Inner tube
1. Inspect:
9Inner tube surface a
Score marksRepair or replace.
Use #1,000 grit wet sandpaper.
Damaged oil lock pieceReplace.
9Inner tube bends
Out of specificationReplace.
Use the dial gauge 1.
NOTE:
The bending value is shown by one half of the
dial gauge reading.
w
Do not attempt to straighten a bent inner
tube as this may dangerously weaken the
tube.
Inner tube bending limit:
0.2 mm (0.008 in)
EC554600
Outer tube
1. Inspect:
9Outer tube 1
Score marks/Wear/DamageReplace.
Adjuster
1. Inspect:
9Adjuster 1
9O-ring 2
Wear/DamageReplace.
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5-33
CHASFRONT FORK
EC555000
ASSEMBLY AND INSTALLATIONEC5551D0
Front fork assembly
1. Wash the all parts in a clean solvent.
2. Stretch the damper assembly fully.
3. Fill:
9Front fork oil 1
To damper assembly.
cC
9Be sure to use recommended fork oil. If
other oils are used, they may have an ex-
cessively adverse effect on the front fork
performance.
9Never allow foreign materials to enter the
front fork.
Recommended oil:
Suspension oil “S1”
Oil capacity:
195cm
3(6.86 Imp oz, 6.59 US oz)
4. After filling, pump the damper assembly 1
slowly up and down (about 200 mm (7.9 in)
stroke) several times to bleed the damper
assembly of air.
NOTE:
Be careful not to excessive full stroke. A
stroke of 200 mm (7.9 in) or more will cause
air to enter. In this case, repeat the steps 2 to
4.
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5-34
CHASFRONT FORK
5. Measure:
9Oil level (left and right) a
Out of specification  Adjust.
Standard oil level:
145~148 mm (5.71~5.83 in)
From top of fully stretched
damper assembly.
6. Tighten:
9Locknut 1
NOTE:
Fully finger tighten the locknut onto the
damper assembly.
7. Loosen:
9Compression damping adjuster 1
NOTE:
9Loosen the compression damping adjuster fin-
ger tight.
9Record the set position of the adjuster (the
amount of turning out the fully turned in posi-
tion).
8. Install:
9Base valve 1
To damper assembly 2.
NOTE:
First bring the damper rod pressure to a maxi-
mum. Then install the base valve while releas-
ing the damper rod pressure.
9. Check that the damper assembly is fully
stretched.
Not fully stretched  Repeat the steps 2 to 8.
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10. Tighten:
9Base valve 1
NOTE:
Hold the damper assembly with the cap bolt
ring wrench
2and use the cap bolt wrench 3
to tighten the base valve with specified torque.
11. After filling, pump the damper assembly 1
slowly up and down more than 10 times to
distribute the fork oil.
5-35
CHASFRONT FORK
12. While protecting the damper assembly 1
with a rag and compressing fully, allow
excessive oil to overflow on the base valve
side.
cC
Take care not to damage the damper
assembly.
13. Allow the overflowing oil to escape at the
hole ain the damper assembly.
14. Check:
9Damper assembly smooth movement
Tightness/Binding/Rough spots  Repeat
the steps 2 to 13.
29 Nm (2.9 m•kg, 21 ft•lb)
Cap bolt wrench:
YM-01500/90890-01500
Cap bolt ring wrench:
YM-01501/90890-01501
1C3-9-32-5B 4/7/06 2:47 PM Page 20

5-36
CHASFRONT FORK
15. Install:
9Dust seal 1
9Stopper ring 2
9Oil seal 3
9Oil seal washer 4
9Slide metal 5
To inner tube 6.
NOTE:
9Apply the fork oil on the inner tube.
9When installing the oil seal, use vinyl seat a
with fork oil applied to protect the oil seal lip.
9Install the oil seal with its manufacture’s marks
or number facing the axle holder side.
9Install the oil seal washer with its projections b
facing upward.
16. Install:
9Piston metal 1
NOTE:
Install the piston metal onto the slot on inner
tube.
17. Install:
9Outer tube 1
To inner tube 2.
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5-37
CHASFRONT FORK
18. Install:
9Slide metal 1
9Oil seal washer 2
To outer tube slot.
NOTE:
Press the slide metal into the outer tube with
fork seal driver 3.
19. Install:
9Oil seal 1
NOTE:
Press the oil seal into the outer tube with fork
seal driver 2.
20. Install:
9Stopper ring 1
NOTE:
Fit the stopper ring correctly in the groove in the
outer tube.
21. Install:
9Dust seal 1
NOTE:
Apply the lithium soap base grease on the inner
tube.
Fork seal driver:
YM-A0948/90890-01502
Fork seal driver:
YM-A0948/90890-01502
1C3-9-32-5B 4/7/06 2:47 PM Page 24

5-39
CHASFRONT FORK
27. Install:
9Push rod 1
9Copper washer 2
9Adjuster 3
To damper assembly 4.
NOTE:
9While compressing the inner tube 5, set the
cap bolt ring wrench 7between the inner tube
and locknut 6.
9Fully finger tighten the adjuster onto the
damper assembly.
28. Inspect:
9Gap abetween adjuster 1and locknut 2.
Out of specificationRetighten and read-
just the locknut.
NOTE:
If the adjuster is installed out of specification,
proper damping force cannot be obtained.
29. Tighten:
9Adjuster (locknut) 1
NOTE:
Hold the locknut 2and tighten the adjuster with
specified torque.
30. Install:
9Adjuster 1
To inner tube.
31. Fill:
9Front fork oil 1
From outer tube top.
*For EUROPE
29 Nm (2.9 m•kg, 21 ft•lb)
55 Nm (5.5 m•kg, 40 ft•lb)
Gap a abetween adjuster and locknut :
0.5~1.0mm (0.02~0.04 in)
Recommended oil:
Suspension oil "S1"
Standard oil amount:
340 cm
3(12.0 Imp oz, 11.5 US oz)
*335 cm
3(11.8 Imp oz, 11.3 US oz)
Extent of adjustment:
300
~380 cm3(10.6~13.4 Imp oz,
10.1~12.8 US oz)
Cap bolt ring wrench:
YM-01501/90890-01501
1C3-9-32-5B 4/7/06 2:47 PM Page 28