2006 YAMAHA YZ250LC length

4-35
CLUTCH AND PRIMARY DRIVEN GEARENG
EC493000
REMOVAL POINTS
EC483211
Clutch boss
1. Remove:
9Nut 1
9Lock washer 2
9Clutch boss 3
NOTE:
Straighten the lock washer tab and use the
clutch holding tool 4, 5to hold the clutch boss.
åFor USA and CDN
∫Except for USA and CDN
EC494000
INSPECTION
EC484100
Clutch housing and boss
1. Inspect:
9Clutch housing 1
Cracks/Wear/Damage  Replace.
9Clutch boss 2
Scoring/Wear/Damage Replace.
EC484201
Primary driven gear
1. Check:
9Circumferential play
Free play exists Replace.
9Gear teeth a
Wear/ Damage Replace.
EC484400
Clutch spring
1. Measure:
9Clutch spring free length a
Out of specification Replace springs as
a set.
Clutch holding tool:
YM-91042................................4 4
90890-04086............................5 5
Clutch spring free length:
Standard
50.0 mm 48.0 mm
(1.969 in) (1.890 in)
å
∫å
1P8-9-31-4B 4/29/05 3:07 PM Page 16

5-31
CHASFRONT FORK
Base valve
1. Inspect:
9Base valve 1
Wear/DamageReplace.
ContaminationClean.
9O-ring 2
Wear/DamageReplace.
9Piston metal 3
Wear/DamageReplace.
9Spring 4
Damage/FatigueReplace base valve.
9Air bleed screw 5
Wear/DamageReplace.
EC554400
Fork spring
1. Measure:
9Fork spring free length a
Out of specificationReplace.
Standard
454 mm 449 mm
(17.9 in) (17.7 in)Fork spring free length:
Collar
1. Inspect:
9Piston metal 1
Wear/Damage Replace.
1P8-9-31-5B 5/12/05 10:57 AM Page 12

5-67
CHASREAR SHOCK ABSORBER
EC5852B5
Rear shock absorber
1. Install:
9Dust seal 1
9O-ring 2
9Collar 3
NOTE:
9Apply the molybdenum disulfide grease on the
dust seal lips and collars.
9Apply the lithium soap base grease on the O-
rings.
2. Install:
9Bush 1
9Collar 2
9Dust seal 3
NOTE:
9Apply the molybdenum disulfide grease on the
bearing and dust seal lips.
9Install the dust seals with their lips facing out-
ward.
4. Adjust:
9Spring length (installed)
Refer to “REAR SHOCK ABSORBER
SPRING PRELOAD ADJUSTMENT” sec-
tion in the CHAPTER 3.
5. Tighten:
9Locknut 1
3. Tighten:
9Adjuster 1
1P8-9-31-5D 4/29/05 2:14 PM Page 26

7-17
SETTINGTUN
EC72P010
Front fork setting parts
9Front fork spring 1
NOTE:
The I.D. mark (slits) ais proved on the end of
the spring.
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 follow-
ing two factors:
1. Setting of spring preload
9Change the set length of the spring.
9Change the spring.
2. Setting of damping force
9Change the rebound damping.
9Change the compression damping.
SPRING SPRINGI.D.
TYPE
RATE PART NUMBERMARK
(slits)
0.398 1C3-23141-A0 I
SOFT 0.408 1C3-23141-B0 II
0.418 1C3-23141-C0 III
STD 0.428 1P8-23141-M0 –
0.438 1C3-23141-E0 IIIII
0.449 1C3-23141-F0 I-I
STIFF 0.459 1C3-23141-G0 I-II
0.469 1C3-23141-H0 I-III
0.479 1C3-23141-J0 I-IIII
EC72C001
Choosing set length
1. Place a stand or block under the engine to
put the rear wheel above the floor, and mea-
sure the length abetween the rear wheel
axle center and the rear fender holding bolt.
1P8-9-31-7 5/19/05 1:31 PM Page 38

7-18
SETTINGTUN
2. Remove the stand or block from the engine
and with a rider astride the seat, measure
the sunken length bbetween the rear wheel
axle center and the rear fender holding bolt.
3. Loosen the locknut 1and make adjustment
by turning the spring adjuster 2to achieve
the standard figure from the subtraction of
the length bfrom the length a.
Standard figure:
90~100 mm (3.5~3.9 in)
NOTE:
9If 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.
9If 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.
1P8-9-31-7 5/19/05 1:31 PM Page 40

7-19
SETTINGTUN
EC72G020
Setting of spring after replacement
After replacement, be sure to adjust the spring to
the set length [sunken length 90~
100 mm (3.5~3.9 in)] and set it.
1. Use of soft spring
9Set 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
9Set 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
low compression damping adjuster on the
softer side.
cC
When using a rear cushion other than cur-
rently installed, use the one whose overall
length
a a
does not exceed the standard as
it may result in faulty performance. Never
use one whose overall length is greater
than standard.
åCoverage of spring by weight
∫Rider weight
1Soft
2Standard
3Stiff
Length a a
of standard shock:
490 mm (19.29 in)
1P8-9-31-7 5/19/05 1:31 PM Page 42

7-20
SETTINGTUN
EC72Q011
Rear shock absorber setting parts
9Rear shock spring 1
[Equal-pitch steel spring ]
[Equal-pitch titanium spring ]
[Unequal-pitch steel spring ]
cC
Install the spring seat 2to the titanium
spring.
NOTE:
9The unequal-pitch spring is softer in initial char-
acteristic than the equal-pitch spring and is diffi-
cult to bottom out under full compression.
9The I.D. color ais marked at the end of the
spring.
SPRING SPRINGI.D.SPRING
TYPE
RATE PART NUMBERCOLORFREE
/POINTLENGTH
SOFT 4.3 5UN-22212-00Brown/1260
5.3 5UN-22212-50
Yellow/1260
5.5 5UN-22212-60 Pink/1 260
STIFF 5.7 5UN-22212-70 White/1 260
SPRING
SPRINGI.D.SPRING
TYPE RATE
PART NUMBERCOLORFREE
(approx.)/POINTLENGTH
SOFT 4.5 5UN-22212-A0 Green/2 275
4.7 5UN-22212-B0 Red/2 275
4.9 5UN-22212-C0 Black/2 275
5.1 5UN-22212-D0 Blue/2 275
5.3 5UN-22212-E0
Yellow/2 275
5.5 5UN-22212-F0 Pink/2 275
STIFF 5.7 5UN-22212-G0
White/2 275
SPRING
TYPESPRING SPRING I.D.FREE
RATE PART NUMBER COLORLENGTH
(approx.)
SOFT4.5 1C3-22212-00Green265
4.7 1C3-22212-10Red265
STD 4.9 1C3-22212-20 Black 265
STIFF 5.1 1C3-22212-30 Blue 265
1P8-9-31-7 5/19/05 1:31 PM Page 44

7-21
SETTINGTUN
9Extent of adjustment (spring length)
[Steel spring]
[Titanium spring]
SPRING FREE EXTENT OF
LENGTH ADJUSTMENT b
260mm (10.24in)240.5~258.5mm(9.47~10.18in)
275mm (10.83in)255.5~273.5mm(10.06~10.77in)
SPRING FREE EXTENT OF
LENGTH ADJUSTMENT b
One I.D. paint mark
245.5~263.5 mm
(9.67~10.37 in)
Approx. 265mmTwo I.D. paint marks
(10.43 in)251.5~269.5 mm
(9.90~10.61 in)
Three I.D. paint marks
243.0~261.0 mm
(9.57~10.28 in)
1P8-9-31-7 5/19/05 1:31 PM Page 46