Disassembling The Crankcase; Checking The Crankcase; Checking The Timing Chain, Crankshaft Sprocket, Timing Chain Guide (Intake Side); Checking The Bearing And Oil Seal - Yamaha XT250X 2008 Service Manual

EAS25570

DISASSEMBLING THE CRANKCASE

1. Remove:
Crankcase bolts
G
NOTE:
Loosen each bolt 1/4 of a turn at a time, in two
stages and in a crisscross pattern. After all of the
bolts are fully loosened, remove them.
2. Turn:
Shift drum segment
G
NOTE:
Turn the shift drum segment to the position
shown in the illustration. In this position, the shift
drum segment's teeth will not contact the crank-
case during crankcase separation.
3. Remove:
Right crankcase
G
EC3C51004
CAUTION:
Tap on one side the crankcase with a
G
soft-face hammer. Tap only reinforced por-
tions of the crankcase.
Do not damage the crankcase mating sur-
G
faces.
Remove the crankcase right halves first.
G
EAS25580

CHECKING THE CRANKCASE

1. Thoroughly wash the crankcase halves in a
mild solvent.
2. Thoroughly clean all the gasket surfaces and
crankcase mating surfaces.
3. Check:
Crankcase
G
Cracks/damage → Replace.
Obstruction → Blow out with compressed air.
EAS3C51011
CHECKING THE TIMING CHAIN,
CRANKSHAFT SPROCKET, TIMING CHAIN
GUIDE (INTAKE SIDE)
1. Check:
Timing chain
G
All manuals and user guides at all-guides.com
5-56
Crack/stiffness → Replace the camshaft
sprocket, timing chain, and crankshaft
sprocket as a set.
2. Check:
Crankshaft sprocket
G
Refer to "CYLINDER HEAD" on page 5-6.
3. Check:
Timing chain guide (intake side)
G
Damage/wear → Replace.
EAS3C51012

CHECKING THE BEARING AND OIL SEAL

1. Check:
Bearing
G
Abnormal sound/rough
ness → Replace.
2. Check:
Oil seal
G
Damage/wear → Replace.
EAS25700

ASSEMBLING THE CRANKCASE

1. Thoroughly clean all the gasket mating sur-
faces and crankcase mating surfaces.
2. Apply:
Sealant
G
(onto the crankcase mating surfaces)
Yamaha bond No. 1215 (Three
Bond No.1215®)
90890-85505
NOTE:
Do not allow any sealant to come into contact
with the oil gallery.
3. Install:
Right crankcase
G
(to the left crankcase)
Crankcase bolt
10 Nm (1.0 m•kg, 7.2 ft•lb)
NOTE:
Turn the shift drum segment as shown so that
G
the shift drum segment teeth do not contact the
CRANKCASE
movement/loose-