Yamaha YZ125 2015, Owner'S Service Manual

Page: 128 / 166

5-19
FRONT FORK
CHECKING THE BASE VALVE
1. Inspect:
• Base valve "1"
Wear/damage
→
Replace.
Contamination
→
Clean.
• O-ring "2"
Wear/damage
→
Replace.
• Piston metal "3"
Wear/damage
→
Replace.
• Spring "4"
Damage/fatigue
→
Replace base
valve.
• Air bleed screw "5"
Wear/damage
→
Replace.
CHECKING THE COLLAR
1. Inspect:
• Contacting surface "a"
Wear/damage
→
Replace.
CHECKING THE FORK SPRING
1. Measure:
• Fork spring free length "a"
Out of specification
→
Replace.
CHECKING THE INNER TUBE
1. Inspect:
• Inner tube surface "a"
Score marks
→
Repair or replace.
Use #1,000 grit wet sandpaper.
Damaged oil lock piece
→
Re-
place.
• Inner tube bends
Out of specification
→
Replace.
Use the dial gauge "1".
The bending value is shown by one
half of the dial gauge reading.
Do not attempt to straighten a bent
inner tube as this may dangerous-
ly weaken the tube.
CHECKING THE OUTER TUBE
1. Inspect:
• Outer tube "1"
Score marks/wear/damage
→
Re-
place.
CHECKING THE ADJUSTER
1. Inspect:
• Adjuster "1"
• O-ring "2"
Wear/damage
→
Replace.
ASSEMBLING THE FRONT FORK
1. Wash the all parts in a clean sol-
vent.
2. Stretch the damper assembly ful-
ly.
3. Fill:
• Front fork oil "1"
To damper assembly.
• Be sure to use recommended
fork oil. If other oils are used,
they may have an excessively ad-
verse effect on the front fork per-
formance.
• Never allow foreign materials to
enter the front fork.
4. After filling, pump the damper as-
sembly "1" slowly up and down
(about 200 mm (7.9 in) stroke)
several times to bleed the damper
assembly of air.
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, re-
peat the steps 2 to 4.
5. Measure:
• Oil level (left and right) "a"
Out of specification
→
Adjust.
Fork spring free length
"a":
454.0 mm (17.87 in)
<Limit>: 449.0 mm
(17.68 in)
Inner tube bending limit:
0.2 mm (0.01 in)
Recommended oil:
Suspension oil "S1"
Oil capacity:
203 cm
3
(7.15 Imp oz,
6.86 US oz)
Standard oil level "a":
145–148 mm (5.71–5.83
in)
From top of fully
stretched damper as-
sembly.