Separating The Crankcase; Checking The Crankcase; Checking The Timing Chain And Timing Chain Guide; Checking The Oil Strainer - Yamaha YZF-R125 Service Manual

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EAS5D71032

SEPARATING THE CRANKCASE

1. Remove:
• Crankcase bolts
NOTE:
Loosen each bolt 1/4 of a turn at a time, in stag-
es and in the proper sequence as shown.
A
B
11
12
3,13
A. Right crankcase
B. Left crankcase
2. Turn:
• Shift drum segment
NOTE:
Turn the shift drum segment "1" to the position
shown in the illustration. In this position, the shift
drum segment teeth will not contact the crank-
case during crankcase separation.
3. Remove:
• Right crankcase
2
1
10,15
9
8
7
4,14
6
5
1
ECA13900
CAUTION:
Tap on one side of the crankcase with a soft-
face hammer. Tap only on reinforced por-
tions of the crankcase, not on the crankcase
mating surfaces. Work slowly and carefully
and make sure the crankcase halves sepa-
rate evenly.
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
Cracks/damage → Replace.
• Oil delivery passages
Obstruction → Blow out with compressed air.
EAS5D71033
CHECKING THE TIMING CHAIN AND TIMING
CHAIN GUIDE
1. Check:
• Timing chain
Damage/stiffness → Replace the timing
chain and camshaft sprocket as a set.
2. Check:
• Timing chain guide (intake side)
Damage/wear → Replace.
EAS5D71034

CHECKING THE OIL STRAINER

1. Check:
• Oil strainer
Damage → Replace.
Contaminants → Clean with solvent.
EAS5D71014

CHECKING THE BEARINGS AND OIL SEAL

1. Check:
• Bearings
Clean and lubricate the bearings, and then
rotate the inner race with your finger.
Rough movement → Replace.
5-59
CRANKCASE