Yamaha XT250X 2008, Service Manual, Page: 161 / 282

CAMSHAFT
5-15
3. Check:
●
Camshaft oil passage
Obstruction
→
Blow out with compressed air.
EAS23880
CHECKING THE ROCKER ARMS AND
ROCKER ARM SHAFTS
The following procedure applies to all of the
rocker arms and rocker arm shafts.
1. Check:
●
Rocker arm
Damage/wear
→
Replace.
2. Check:
●
Rocker arm shaft
Blue discoloration/excessive wear/pitting/
scratches
→
Replace or check the lubrication
system.
3. Measure:
●
Rocker arm inside diameter “a”
Out of specification
→
Replace.
4. Measure:
●
Rocker arm shaft outside diameter “a”
Out of specification
→
Replace.
5. Calculate:
●
Rocker-arm-to-rocker-arm-shaft clearance
NOTE:
Calculate the clearance by subtracting the rock-
er arm shaft outside diameter from the rocker
arm inside diameter.
Out of specification
→
Replace the defective
part(s).
EAS24040
INSTALLING THE CAMSHAFT AND
ROCKER ARMS
1. Lubricate:
●
Rocker arm
●
Rocker arm shafts
2. Install:
●
Exhaust rocker arm “1”
●
Exhaust rocker arm shaft “2”
NOTE:
The exhaust rocker arm shaft must be inserted
into the cylinder head completely.
Rocker arm inside diameter
12.000
–
12.018 mm
(0.4724
–
0.4731 in)
Limit
12.036 mm (0.4739 in)
Rocker arm shaft outside diame-
ter
11.981
–
11.991 mm
(0.4717
–
0.4721 in)
Limit
11.950 mm (0.4705 in)
Rocker-arm-to-rocker-arm-shaft
clearance
0.009
–
0.037 mm (0.0004
–
0.0015
in)
Recommended lubricant
Rocker arm
Molybdenum-disulfide oil
Rocker arm shaft
Engine oil
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