2007 YAMAHA YZ250F clutch

4 - 53
ENGCLUTCH
Friction plate
1. Measure:
Friction plate thickness
Out of specification → Replace friction
plate as a set.
Measure at all four points.
EC484600
Clutch plate
1. Measure:
Clutch plate warpage
Out of specification → Replace clutch
plate as a set.
Use a surface plate 1 and thickness
gauge 2.
Friction plate thickness:
2.9 ~ 3.1 mm
(0.114 ~ 0.122 in)
: 2.7 mm (0.106 in)
Warp limit:
0.1 mm (0.004 in)
Push lever shaft
1. Inspect:
Push lever shaft 1
Wear/damage → Replace.
Push rod
1. Inspect:
Push rod 1 1
Bearing 2
Washer 3
Push rod 2 4
Ball 5
Wear/damage/bend → Replace.

4 - 54
ENGCLUTCH
EC4A5000
ASSEMBLY AND INSTALLATION
Push lever shaft
1. Install:
Push lever shaft 1
Bolt (push lever shaft) 2
NOTE:
Apply the lithium soap base grease on the oil
seal lip.
Apply the engine oil on the push lever shaft.
Fit the seat plate 3 in the groove a of the
push lever shaft and tighten the bolt (seat
plate).
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
Clutch
1. Install:
Primary driven gear 1
Thrust washer 2
Clutch boss 3
NOTE:
Apply the engine oil on the primary driven gear
inner circumference.
2. Install:
Lock washer 1
Nut (clutch boss) 2
NOTE:
Use the clutch holding tool 3 to hold the clutch
boss.
È
For USA and CDN
ÉExcept for USA and CDN
Clutch holding tool:
YM-91042/90890-04086
T R..60 Nm (6.0 m · kg, 43 ft · lb)
È
É

4 - 55
ENG
3. Bend the lock washer 1 tab.
4. Install:
Seat plate 1
Cushion spring 2
NOTE:
Install the seat plate with its chamfered por-
tion a facing the clutch boss 3.
Install the seat plate so that it is not caught
on the step b.
Install the cushion spring with its concave
surface c facing outward.
1
2
3
a
bc
5. Install:
Friction plate 1 1
Clutch plate 1 2
Friction plate 2 3
Clutch plate 2 4
NOTE:
Install the clutch plates and friction plates
alternately on the clutch boss, starting with a
friction plate and ending with a friction plate.
Use the friction plates 1 for the first and final
while paying attention to the difference in
surface pattern.
Apply the engine oil on the friction plates and
clutch plates.
Unlike the clutch plate 2, the clutch plate 1
has no surface gloss. Use the clutch plate 1
for the first while paying attention to the dif-
ference in surface gloss.
6. Install:
Bearing 1
Washer 2
Circlip 3
To push rod 1 4.
NOTE:
Apply the engine oil on the bearing and
washer.
CLUTCH

4 - 56
ENGCLUTCH
7. Install:
Push rod 2 1
Ball 2
Push rod 1 3
NOTE:
Apply the engine oil on the push rod 1, 2 and
ball.
8. Install:
Pressure plate 1
9. Install:
Clutch spring 1
Bolt (clutch spring) 2
NOTE:
Tighten the bolts in stage, using a crisscross
pattern.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
10. Install:
Dowel pin 1
Gasket (clutch cover) 2
11. Install:
Clutch cover 1
Bolt (clutch cover)
NOTE:
Tighten the bolts in stage, using a crisscross
pattern.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)

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ENGBALANCER
BALANCER
Extent of removal:
1 Balancer shaft drive gear
2 Balancer shaft
Extent of removal Order Part name Q’ty Remarks
BALANCER REMOVAL
Preparation for removal Primary driven gear Refer to “CLUTCH” section.
Right crankcase cover Refer to “OIL FILTER ELEMENT,
WATER PUMP AND RIGHT CRANK-
CASE COVER” section.
Stator Refer to “CDI MAGNETO” section.
1 Nut (primary drive gear) 1
Refer to “REMOVAL POINTS”.
2 Nut (balancer shaft driven gear) 1
3 Lock washer 1
4 Primary drive gear 1
5 Balancer shaft drive gear 1
6 Lock washer 1
7 Balancer shaft driven gear 1
8 Balancer shaft 1 Refer to “REMOVAL POINTS”.
2
1
2

4 - 67
ENGOIL PUMP
OIL PUMP
Extent of removal:
1 Oil pump removal
2 Oil pump disassembly
Extent of removal Order Part name Q’ty Remarks
OIL PUMP REMOVAL AND DIS-
ASSEMBLY
Preparation for removal Primary driven gear Refer to “CLUTCH” section.
Right crankcase cover Refer to “OIL FILTER ELEMENT,
WATER PUMP AND RIGHT CRANK-
CASE COVER” section.
1 Circlip 1
2 Washer 1
3 Oil pump drive gear 1
4 Oil pump assembly 1
5 Outer rotor 2 1
6 Circlip 1
7 Inner rotor 2 1
8 Dowel pin 1
9 Oil pump cover 1
10 Outer rotor 1 1
11 Inner rotor 1 1
2
1

4 - 84
ENGENGINE REMOVAL
EC4M0000
ENGINE REMOVAL
Extent of removal Order Part name Q’ty Remarks
ENGINE REMOVAL
Preparation for removal Hold the machine by placing the
suitable stand under the frame.
WARNING
Support the machine securely so
there is no danger of it falling over.
Seat and fuel tank Refer to “SEAT, FUEL TANK AND SIDE
COVERS” section.
Carburetor Refer to “CARBURETOR” section.
Exhaust pipe and silencer Refer to “EXHAUST PIPE AND
SILENCER” section.
Clutch cable Disconnect at engine side.
Radiator Refer to “RADIATOR” section.
Shift pedal Refer to “KICK SHAFT AND SHIFT
SHAFT” section.
Cylinder head breather hose Refer to “CAMSHAFTS” section.
Drain the engine oil. Refer to “ENGINE OIL REPLACEMENT”
section in the CHAPTER 3.
Oil hose and oil tank breather
hoseRefer to “OIL PUMP” section.

4 - 90
ENGCRANKCASE AND CRANKSHAFT
Extent of removal Order Part name Q’ty Remarks
4 Bolt [L = 45 mm (1.77 in)] 6
Refer to “REMOVAL POINTS”. 5 Bolt [L = 55 mm (2.17 in)] 1
6 Bolt [L = 70 mm (2.76 in)] 4
7 Hose guide 1
8 Clutch cable holder 1
9 Right crankcase 1
10 Left crankcase 1
11 Oil strainer 1
12 Crankshaft 1 Use special tool.
Refer to “REMOVAL POINTS”.
2
1