2002 YAMAHA YZ250F clutch

3 - 15
INSP
ADJ
ENGINE OIL REPLACEMENT
(Except for USA and CDN)
CAUTION:
Do not add any chemical additives or use
oils with a grade of CD a or higher.
Do not use oils labeled “ENERGY CON-
SERVING II” b or higher. Engine oil also
lubricates the clutch and additives could
cause clutch slippage.
Do not allow foreign materials to enter the
crankcase.
5. Install:
Oil tank cap
6. Start the engine and let it warm up for
several minutes.
7. Turn off the engine and inspect the oil
level once again.
NOTE:
Wait a few minutes until the oil settles before
inspecting the oil level.
Recommended oil:
Refer to the following chart for
selection of oils which are suited
to the atmospheric temperatures.
Recommended engine oil classi-
fication:
API STANDARD:
API “SH” or higher grade
(Designed primarily for motor-
cycles)
-20
-4-10
140
3010
5020
6830
8640 50
104
122°CTemp.
°F
10W-30
10W-40
20W-40
20W-50
15W-40
a
b
ENGINE OIL REPLACEMENT
1. Start the engine and warm it up for sev-
eral minutes, and then turn off the engine
and wait for five minute.
2. Place the machine on a level place and
hold it on upright position by placing the
suitable stand under the engine.
3. Place a suitable container under the
engine.

3 - 45
INSP
ADJ
LUBRICATION
LUBRICATION
To ensure smooth operation of all compo-
nents, lubricate your machine during setup,
after break-in, and after every race.
1All control cable
2Clutch lever pivot
3Shift pedal pivot
4Footrest pivot
5Throttle-to-handlebar contact
6Drive chain
7Tube guide cable winding portion
8Throttle cable end
9Clutch cable end
0Decompression cable endÅUse Yamaha cable lube or equivalent on these
areas.
ıUse SAE 10W-30 motor oil or suitable chain
lubricants.
ÇLubricate the following areas with high quality,
lightweight lithium-soap base grease.
CAUTION:
Wipe off any excess grease, and avoid get-
ting grease on the brake discs.
AAA
AAB
CC

4 - 49
ENGCLUTCH
EC4A0000
CLUTCH
Extent of removal:1 Push rod 1, 2 and push lever shaft removal2 Push pod 1 disassembly
3 Friction plate and clutch plate removal4 Primary driven gear removal
Extent of removal Order Part name Q’ty Remarks
CLUTCH REMOVAL
Preparation for removal Drain the engine oil. Refer to “ENGINE OIL REPLACEMENT”
section in the CHAPTER 3.
Brake pedal Refer to “ENGINE REMOVAL” section.
Clutch cable Disconnect at engine side.
1 Clutch cover 1
2 Clutch spring 5
3 Pressure plate 1
4 Push rod 1 1
5 Circlip 1
6 Washer 1
7 Bearing 1
8 Ball 1
9Push rod 2
1
4
1
12
3

4 - 50
ENGCLUTCH
Extent of removal Order Part name Q’ty Remarks
10 Friction plate 9
11 Clutch plate 8
12 Cushion spring 1
13 Seat plate 1
14 Nut (clutch boss) 1
Use special tool.
Refer to “REMOVAL POINTS”. 15 Look washer 1
16 Clutch boss 1
17 Thrust washer 1
18 Primary driven gear 1
19Push lever shaft
1
4
1
3

4 - 51
ENGCLUTCH
EC4A3000
REMOVAL POINTS
Clutch boss
1. Remove:
Nut 1
Lock washer 2
Clutch boss 3
NOTE:
Straighten the lock washer tab and use the
clutch holding tool 4 to hold the clutch boss.
ÅFor USA and CDN
ıExcept for USA and CDN
Clutch holding tool:
YM-91042/90890-04086Å
ı
EC4A4000
INSPECTION
EC484100
Clutch housing and boss
1. Inspect:
Clutch housing 1
Cracks/wear/damage → Replace.
Clutch boss 2
Scoring/wear/damage → Replace.
EC484201
Primary driven gear
1. Check:
Circumferential play
Free play exists → Replace.
Gear teeth a
Wear/damage → Replace.
Clutch spring
1. Measure:
Clutch spring free length a
Out of specification → Replace springs
as a set.
Clutch spring free length:
40.4 mm (1.59 in)
: 39.4 mm (1.55 in)

4 - 52
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 - 53
ENG

CLUTCH
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.
Å
For USA and CDN
ı
Except for USA and CDN
Clutch holding tool:
YM-91042/90890-04086
T R..60 Nm (6.0 m · kg, 43 ft · lb)
Å
ı

4 - 54
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 the paint c
facing out.
1
2
c
3
a
b
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 attenion to the differ-
ence 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