lock YAMAHA YZ250LC 2005 Manuale duso (in Italian)

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
1P8-9-30-4B 11/5/04 10:59 AM Page 16

4-37
CLUTCH AND PRIMARY DRIVEN GEARENG
EC495230
Clutch
1. Install:
9Thrust plate [D=ø 42 mm (1.65 in)] 1
9Spacer 2
9Bearing 3
9Primary driven gear 4
NOTE:
Apply the transmission oil on the bearing, spacer
and primary driven gear inner circumference.
2. Install:
9Thrust plate [D=ø 44 mm (1.73 in)] 1
9Clutch boss 2
3. Install:
9Lock washer 1
9Nut (clutch boss) 2
NOTE:
Use the clutch holding tool 3, 4to hold the
clutch boss.
åFor USA and CDN
∫Except for USA and CDN
4. Bend the lock washer 1tab.
75 Nm (7.5 m•kg, 54 ft•lb)
Clutch holding tool:
YM-91042 ..............................3 3
90890-04086 ..........................4 4
å
∫
1P8-9-30-4B 11/5/04 10:59 AM Page 20

4-46
KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEARENG
EC4C5420
Kick idle gear
1. Install:
9Kick idle gear 1
9Plain washer 2
9Circlip 3
NOTE:
9Apply the transmission oil on the kick idle gear
inner circumference.
9Install the kick idle gear with its depressed side
atoward you.
3. Install:
9Spring guide 1
NOTE:
Slide the spring guide into the kick axle, make
sure the groove ain the spring guide fits on the
stopper of the torsion spring.
4. Install:
9Plain washer 1
9Kick axle assembly 2
NOTE:
9Apply the molybdenum disulfide grease on the
contacting surfaces of the kick axle stopper a
and stopper plate 3.
9Apply the transmission oil on the kick axle.
9Slide the kick axle assembly into the crankcase
and make sure the kick axle stopper fits into
the stopper plate.
5. Hook:
9Torsion spring 1
NOTE:
Turn the torsion spring clockwise and hook into
the proper hole ain the crankcase.
1P8-9-30-4B 11/5/04 10:59 AM Page 38

4-57
CDI MAGNETOENG
EC4L5000
ASSEMBLY AND INSTALLATION
EC4L5172
CDI magneto
1. Install:
9Stator 1
9Screw (stator) 2
NOTE:
Temporarily tighten the screw (stator) at this
point.
2. Remove:
9Rotor 1
Use the flywheel puller 2.
NOTE:
When installing the flywheel puller, turn it coun-
terclockwise.
EC4L3000
REMOVAL POINTS
EC4L3102
Rotor
1. Remove:
9Nut (rotor) 1
9Plain washer 2
Use the rotor holding tool 3.
EC4L4000
INSPECTION
EC4L4101
CDI magneto
1. Inspect:
9Rotor inner surface a
9Stator outer surface b
Damage
Inspect the crankshaft runout
and crankshaft bearing.
If necessary, replace CDI magneto and/or
stator.
EC4L4200
Woodruff key
1. Inspect:
9Woodruff key 1
Damage
Replace.
Rotor holding tool:
YU-1235/90890-01235
Flywheel puller:
YM-1189/90890-01189
1P8-9-30-4C 21/5/04 12:59 PM Page 16

4-61
ENGINE REMOVALENG
Extent of removal:1Engine removal
Extent of removal Order Part name Q’ty Remarks
1 Chain cover 1
2 Nut (drive sprocket) 1
3 Lock washer 1 Refer to “REMOVAL POINTS”.
4 Drive sprocket 1
5 Clip 1
6 Bolt (brake pedal) 1
7 Brake pedal 1
8 Engine bracket 2
9 Engine mounting bolt 3
10 Pivot shaft 1 Remove completely.
11 Engine 1 Refer to “REMOVAL POINTS”.
1





26 Nm (2.6 m•kg, 19 ft•lb)
64 Nm (6.4 m•kg, 46 ft•lb)
75 Nm (7.5 m•kg, 54 ft•lb)
8 Nm (0.8 m•kg, 5.8 ft•lb)
34 Nm (3.4 m•kg, 24 ft•lb)
64 Nm (6.4 m•kg, 46 ft•lb)
85 Nm (8.5 m•kg, 61 ft•lb)
1P8-9-30-4C 21/5/04 12:59 PM Page 24

4-62
ENGINE REMOVALENG
EC4M3340
Engine removal
NOTE:
Make sure that the couplers, hoses and cables
are disconnected.
1. Lift the engine 1up to the point where the
engine’s mounting front does not contact the
bracket on the frame.
2. Remove the engine 1aslant and upward
while inclining it toward the kick crank side
so that the engine’s mounting top does not
contact the bracket on the frame.
EC4M3000
REMOVAL POINTS
EC4F3100
Drive sprocket
1. Remove:
9Nut (drive sprocket) 1
9Lock washer 2
NOTE:
9Straighten the lock washer tab.
9Loosen the nut while applying the rear brake.
2. Remove:
9Drive sprocket 1
9Drive chain 2
NOTE:
Remove the drive sprocket together with the
drive chain.
1P8-9-30-4C 21/5/04 1:00 PM Page 26

4-64
ENGINE REMOVALENG
4. Install:
9Chain guide 1
9Chain cover 2
9Screw (chain cover) 3 2. Install:
9Lock washer 1
9Nut (drive sprocket) 2
NOTE:
Tighten the nut while applying the rear brake.
3. Bend the lock washer tab to lock the nut.
8 Nm (0.8 m•kg, 5.8 ft•lb)
75 Nm (7.5 m•kg, 54 ft•lb)
EC4M5341
Drive sprocket
1. Install:
9Drive sprocket 1
9Drive chain 2
NOTE:
Install the drive sprocket together with the drive
chain.
1P8-9-30-4C 21/5/04 1:00 PM Page 30

4-71
CRANKCASE AND CRANKSHAFTENG
8. Tighten:
9Segment 1
9Bolt (segment) 2
NOTE:
9When installing the segment onto the shift cam
3, align the punch mark awith the dowel pin
b.
9Turn the segment clockwise until it stops and
tighten the bolt.
30 Nm (3.0 m•kg, 22 ft•lb)
7. Install:
9Tension spring 1
9Holder 2
9Bolt (holder) 3
NOTE:
Install the holder so that it contacts the projec-
tion aon the crankcase (right).
10 Nm (1.0 m•kg, 7.2 ft•lb)
9. Remove:
9Sealant
Forced out on the cylinder mating surface.
10. Apply:
9Engine oil
To the crank pin, bearing, oil delivery hole
and connecting rod big end washer.
11. Check:
9Crankshaft and transmission operation
Unsmooth operation
Repair.
14 Nm (1.4 m•kg, 10 ft•lb)
6. Install:
9Bolt (crankcase) 1
NOTE:
Tighten the crankcase tightening bolts in stage,
using a crisscross pattern.
1P8-9-30-4C 21/5/04 1:00 PM Page 44

5-9
CHASFRONT WHEEL AND REAR WHEEL
8. Install:
9Chain puller (right) 1
9Plain washer 2
9Nut (wheel axle) 3
NOTE:
Temporarily tighten the nut (wheel axle) at this
point.
9. Adjust:
9Drive chain slack a
Refer to “DRIVE CHAIN SLACK ADJUSTMENT”
section in the CHAPTER 3.
10. Tighten:
9Nut (wheel axle) 1
9Locknut 2
125 Nm (12.5 m•kg, 90 ft•lb)
Drive chain slack :
48~58 mm (1.9~2.3 in)
16 Nm (1.6 m•kg, 11 ft•lb)
1P8-9-30-5A 19/5/04 9:28 AM Page 18

5-14
CHASFRONT BRAKE AND REAR BRAKE
EC5A3000
REMOVAL POINTS
EC5A3101
Brake fluid
1. Remove:
[Front]
9Master cylinder cap 1
[Rear]
9Master cylinder cap 1
9Protector
NOTE:
Do not remove the diaphragm.
AFront
BRear
2. Connect the transparent hose 2to the
bleed screw 1and place a suitable contain-
er under its end.
AFront
BRear
3. Loosen the bleed screw and drain the brake
fluid while pulling the lever in or pushing
down on the pedal.
cC
9Do not reuse the drained brake fluid.
9Brake fluid may erode painted surfaces or
plastic parts. Always clean up spilled fluid
immediately.
EC533301
Caliper piston
1. Remove:
9Caliper piston
Use compressed air and proceed carefully.
w
9Cover piston with rag and use extreme cau-
tion when expelling piston from cylinder.
9Never attempt to pry out piston.
AFront
BRear
Caliper piston removal steps:
9Insert a piece of rag into the caliper to lock
one caliper.
9Carefully force the piston out of the caliper
cylinder with compressed air.
1P8-9-30-5A 19/5/04 9:28 AM Page 28