clutch YAMAHA YZ250LC 2005 Owner's Manual

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

4-36
CLUTCH AND PRIMARY DRIVEN GEARENG
EC484500
Friction plate
1. Measure:
9Friction plate thickness
Out of specification Replace friction
plate as a set.
Measure at all four points.
EC484600
Clutch plate
1. Measure:
9Clutch plate warpage
Out of specification Replace clutch plate
as a set.
Use a surface plate 1and thickness
gauge 2.
EC484700
Push lever axle
1. Inspect:
9Push lever axle 1
Wear/Damage Replace.
EC484810
Push rod
1. Inspect:
9Push rod 1 1
9Bearing 2
9Plain washer 3
9Push rod 2 4
Wear/Damage/Bend Replace.
EC495000
ASSEMBLY AND INSTALLATION
EC485120
Push lever axle
1. Install:
9Push lever axle 1
9Copper washer 2
9Bolt (push lever axle) 3
NOTE:
Apply the lithium soap base grease on the oil
seal lip and push lever axle.
Friction plate thickness:
Standard
2.9~3.1 mm 2.8 mm
(0.114~0.122 in) (0.110 in)
Warp limit:
0.2 mm (0.008 in)
6 Nm (0.6 m•kg, 4.3ft•lb)
1P8-9-30-4B 11/5/04 10:59 AM Page 18

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

4-38
CLUTCH AND PRIMARY DRIVEN GEARENG
5. Install:
9Friction plate 1
9Clutch plate 2
NOTE:
9Install the clutch plates and friction plates alter-
nately on the clutch boss, starting with a friction
plate and ending with a friction plate.
9Apply the transmission oil on the friction plates
and clutch plates.
6. Install:
9Bearing 1
9Plain washer 2
9Circlip 3
To push rod 1 4.
NOTE:
Apply the lithium soap base grease on the bear-
ing and plain washer.
7. Install:
9Push rod 2 1
9Push rod 1 2
NOTE:
9Apply the transmission oil on the ends of the
push rod 2.
9Install the push rod 2 with its smaller end a
toward you.
8. Install:
9Pressure plate 1
9. Install:
9Clutch spring 1
9Screw (clutch spring) 2
NOTE:
Tighten the screws in stage, using a crisscross
pattern.
10 Nm (1.0 m•kg, 7.2 ft•lb)
1P8-9-30-4B 11/5/04 10:59 AM Page 22

4-39
CLUTCH AND PRIMARY DRIVEN GEARENG
10. Install:
9O-ring 1
To clucth cover.
11. Install:
9Clutch cover 1
9Bolt (clutch cover) 2
NOTE:
Tighten the bolts in stage, using a crisscross
pattern.
12. Install:
9O-ring 1
9Clutch cable 2
NOTE:
Apply the lithium soap base grease on the O-
ring.
10 Nm (1.0 m•kg, 7.2 ft•lb)
1P8-9-30-4B 11/5/04 10:59 AM Page 24

4-40
KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEARENG
Extent of removal Order Part name Q’ty Remarks
RPIMARY DRIVE GEAR REMOVAL
Preparation for Drain the transmission oil.Refer to “TRANSMISSION OIL REPLACE-
removalMENT“ section in the CHAPTER 3.
Bolt (brake pedal) Shift the brake pedal downward.
Radiator hose 4 Disconnect at water pump side.
Bolt (push rod)
Refer to “CYLINDER HEAD, CYLINDER
AND PISTON” section.
1 Kick starter 1
2 Crankcase cover (right) 1
3 Bolt (Primary drive gear) 1 Only loosening
Refer to “REMOVAL POINTS”.
4 Primary driven gear 1 Refer to “CLUTCH AND PRIMARY
DRIVEN GEAR”section.
5 Primary drive gear 1
6 Thrust plate 1
EC4C0000
KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEAREC4C8000
PRIMARY DRIVE GEAR
1
Extent of removal:1Primary drive gear removal
30 Nm (3.0 m•kg, 22 ft•lb)
10 Nm (1.0 m•kg, 7.2 ft•lb)
55 Nm (5.5 m•kg, 40 ft•lb)
1P8-9-30-4B 11/5/04 10:59 AM Page 26

4-47
KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEARENG
5. Install:
9Crankcase cover (right) 1
NOTE:
Mesh the governor gear 2with the governor
drive gear 3and the impeller shaft gear 4with
the primary drive gear 5.
4. Install:
9Dowel pin 1
9Gasket [crankcase cover (right)] 2
3. Tighten:
9Bolt (primary drive gear) 1
NOTE:
Place an aluminum plate abetween the teeth of
the primary drive gear 2and driven gear 3.
EC4C5531
Primary drive gear
1. Install:
9Thrust plate 1
9Primary drive gear 2
9Governor drive gear 3
9Plain washer 4
9Bolt (primary drive gear) 5
NOTE:
9Install the plain washer with its chamfered side
atoward you.
9Temporarily tighten the bolt at this point.
2. Install:
9Primary driven gear
Refer to “CLUTCH AND PRIMARY DRI-
VEN GEAR” section.
55 Nm (5.5 m•kg, 40 ft•lb)
1P8-9-30-4B 11/5/04 10:59 AM Page 40

4-48
KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEARENG
8. Install:
9Shift pedal 1
9Bolt (shift pedal) 2
NOTE:
Install the shift pedal so that the top of the shift
pedal outer diameter ais highest without
exceeding the line bconnecting the center of
the shift shaft and bottom of the screw
[crankcase cover (left)] 3.
7. Install:
9Kick starter 1
9Plain washer 2
9Bolt (kick starter) 3
NOTE:
Install the kick starter closest to but not contact-
ing the clutch cover mounting boss a.
6. Install:
9Bolt [crankcase cover (right)] 1
NOTE:
Tighten the bolts in stage, using a crisscross
pattern.
30 Nm (3.0 m•kg, 22 ft•lb)
10 Nm (1.0 m•kg, 7.2 ft•lb)
10 Nm (1.0 m•kg, 7.2 ft•lb)
1P8-9-30-4B 11/5/04 10:59 AM Page 42

4-60
ENGINE REMOVALENG
Extent of removal Order Part name Q’ty Remarks
ENGINE REMOVAL
Preparation for
Hold the machine by placing the
removalsuitable stand under the engine.
Seat and fuel tankRefer to “SEAT, FUEL TANK AND
SIDE COVERS” section.
CarburetorRefer to “CARBURETOR AND REED
VALVE” section.
Exhaust pipe and silencer Refer to “EXHAUST PIPE AND
Exhaust pipe stay (rear) SILENCER” section.
Clutch cable Disconnect at engine side.
Radiator Refer to “RADIATOR” section.
Spark plug
Disconnect the CDI magneto lead.
EC4M0000
ENGINE REMOVAL
w
Support the machine securely so there is no dan-
ger of it falling over.



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 22

5-41
CHASHANDLEBAR
Extent of removal Order Part name Q’ty Remarks
Preparation forHANDLEBAR REMOVAL
removal
Number plate Remove the clamp portion only.
1 Clutch cable 1 Disconnect at the lever side.
2 Clutch lever holder 1
3 “ENGINE STOP” button 1
4 Master cylinder 1 Refer to “REMOVAL POINTS”.
5 Throttle cable cap 1 Turn over the cap cover.
6 Throttle cable 1 Disconnect at the throttle side.
7 Throttle 1 Loosen the bolts.
8 Cap cover 1
9 Collar 1
10 Grip (left) 1 Refer to “REMOVAL POINTS”.
11 Handlebar holder (upper) 2
12 Handlebar 1
EC5B0000
HANDLEBAR
1
Extent of removal:1Handlebar removal
1 Nm (0.1 m•kg, 0.7 ft•lb)
4 Nm (0.4 m•kg, 2.9 ft•lb)
9 Nm (0.9 m•kg, 6.5 ft•lb)
28 Nm (2.8 m•kg, 20 ft•lb)
4 Nm (0.4 m•kg, 2.9 ft•lb)
4 Nm (0.4 m•kg, 2.9 ft•lb)
1P8-9-30-5C 11/5/04 11:09 AM Page 2