Checking The Rocker Arms And Rocker Arm Shafts; Installing The Camshaft And Rocker Arms - Yamaha XT250X Service Manual

3. Check:
Camshaft oil passage
G
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
G
Damage/wear → Replace.
2. Check:
Rocker arm shaft
G
Blue discoloration/excessive wear/pitting/
scratches → Replace or check the lubrication
system.
3. Measure:
Rocker arm inside diameter "a"
G
Out of specification → Replace.
Rocker arm inside diameter
12.000–12.018 mm
(0.4724–0.4731 in)
Limit
12.036 mm (0.4739 in)
4. Measure:
Rocker arm shaft outside diameter "a"
G
Out of specification → Replace.
Rocker arm shaft outside diame-
ter
11.981–11.991 mm
(0.4717–0.4721 in)
Limit
11.950 mm (0.4705 in)
5. Calculate:
Rocker-arm-to-rocker-arm-shaft clearance
G
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).
Rocker-arm-to-rocker-arm-shaft
clearance
0.009–0.037 mm (0.0004–0.0015
in)
EAS24040
INSTALLING THE CAMSHAFT AND
ROCKER ARMS
1. Lubricate:
Rocker arm
G
Rocker arm shafts
G
Recommended lubricant
Rocker arm
Molybdenum-disulfide oil
Rocker arm shaft
Engine oil
2. Install:
Exhaust rocker arm "1"
G
Exhaust rocker arm shaft "2"
G
NOTE:
The exhaust rocker arm shaft must be inserted
into the cylinder head completely.
5-15
CAMSHAFT