2005 YAMAHA YZ250LC oil

5-24
CHASFRONT BRAKE AND REAR BRAKE
2. Install:
9Brake hose holder 1
9Screw (brake hose holder) 2
cC
After installing the brake hose holders,
make sure the brake hose does not contact
the spring (rear shock absorber). If it does,
correct its twist.
EC5A5620
Brake fluid
1. Fill:
9Brake fluid
Until the fluid level reaches “LOWER” level
line a.
w
9Use only the designated quality brake fluid:
otherwise, the rubber seals may deterio-
rate, causing leakage and poor brake per-
formance.
9Refill with the same type of brake fluid;
mixing fluids may result in a harmful chemi-
cal reaction and lead to poor performance.
9Be 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 vapor lock.
cC
Brake fluid may erode painted surfaces or
plastic parts. Always clean up spilled fluid
immediately.
AFront
BRear
Recommended brake fluid:
DOT #4
1 Nm (0.1 m•kg, 0.7 ft•lb)
1P8-9-30-5A 19/5/04 9:29 AM Page 48

5-27
CHASFRONT FORK
Extent of removal Order Part name Q’ty Remarks
FRONT FORK DISASSEMBLY
1Adjuster 1 Drain the fork oil. Use special tool.
Refer to “REMOVAL POINTS”.
2Fork spring 1
3Dust seal 1
4Stopper ring 1 Refer to “REMOVAL POINTS”.
5Inner tube 1
6Outer tube 1
7Piston metal 1
8Slide metal 1
9Oil seal washer 1
0Oil seal 1
qBase valve 1 Drain the fork oil. Use special tool.
wDamper assembly 1 Refer to “REMOVAL POINTS”.
EC558000
FRONT FORK DISASSEMBLY
1
Extent of removal:1Oil seal removal2Damper rod removal
2






29 Nm (2.9 m•kg, 21 ft•lb)
1 Nm (0.1 m•kg, 0.7 ft•lb)
30 Nm (3.0 m•kg, 22 ft•lb)
55 Nm (5.5 m•kg, 40 ft•lb)
29 Nm (2.9 m•kg, 21 ft•lb)
1P8-9-30-5B 20/5/04 2:11 PM Page 4

5-28
CHASFRONT FORK
EC556000
HANDLING NOTE
NOTE:
The front fork requires careful attention. So it is
recommended that the front fork be maintained
at the dealers.
cC
To prevent an accidental explosion of air,
the following instructions should be ob-
served:
9The front fork with a built-in piston rod
has a very sophisticated internal con-
struction and is particularly sensitive to
foreign material.
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.
9Before removing the base valves or front
forks, be sure to extract the air from the air
chamber completely.
EC553000
REMOVAL POINTS
EC553311
Damper assembly
1. Loosen:
9Damper assembly 1
NOTE:
Before removing the front fork from the
machine, loosen the damper assembly with
the cap bolt ring wrench 2.
Cap bolt ring wrench:
YM-01501/90890-01501
1P8-9-30-5B 20/5/04 2:11 PM Page 6

5-29
CHASFRONT FORK
Adjuster
1. Drain the outer tube of its front fork oil at its
top.
2. Loosen:
9Adjuster 1
3. Remove:
9Adjuster 1
NOTE:
9While compressing the inner tube 2, set the
cap bolt ring wrench 4between the inner tube
and locknut 3.
9Hold the locknut and remove the adjuster.
cC
Do not remove the locknut as it may go
into the damper assembly and not be taken
out.
Cap bolt ring wrench:
YM-01501/90890-01501
EC553201
Inner tube
1. Remove:
9Dust seal 1
9Stopper ring 2
Using slotted-head screwdriver.
cC
Take care not to scratch the inner tube.
2. Remove:
9Inner tube 1
Oil seal removal steps:
9Push in slowly athe inner tube just be-
fore it bottoms out and then pull it back
quickly b.
9Repeat this step until the inner tube can
be pulled out from the outer tube.
1P8-9-30-5B 20/5/04 2:11 PM Page 8

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
1P8-9-30-5B 20/5/04 2:11 PM Page 10

5-31
CHASFRONT FORK
Base valve
1. Inspect:
9Base valve 1
Wear/DamageReplace.
ContaminationClean.
9O-ring 2
Wear/DamageReplace.
9Bush 3
Wear/DamageReplace base valve.
9Spring 4
Damage/FatigueReplace base valve.
9Air bleed screw 5
Wear/DamageReplace base valve.
EC554400
Fork spring
1. Measure:
9Fork spring free length a
Out of specificationReplace.
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.
Standard
465 mm 460 mm
(18.3 in) (18.1 in)Fork spring free length:
Inner tube bending limit:
0.2 mm (0.008 in)
1P8-9-30-5B 20/5/04 2:11 PM Page 12

5-32
CHASFRONT FORK
EC554600
Outer tube
1. Inspect:
9Outer tube 1
Score marks/Wear/DamageReplace.
Adjuster
1. Inspect:
9Adjuster 1
9O-ring 2
Wear/DamageReplace.
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)
1P8-9-30-5B 20/5/04 2:11 PM Page 14

5-33
CHASFRONT FORK
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.
5. Inspect:
9Oil amount
While keeping the damper assembly fully
stretched, check that the oil is above the
step aon the damper assembly.
Below the stepReplenish fork oil above
the step.
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.
1P8-9-30-5B 20/5/04 2:11 PM Page 16