Disassembling The Crankcase; Checking The Timing Chain, Timing Chain Guide, Oil Strainer; Checking The Crankcase - Yamaha WR450FB 2012 Owner's Service Manual

EAS25570

DISASSEMBLING THE CRANKCASE

1. Separate:
• Right crankcase
• Left crankcase
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a. Remove the crankcase bolts, hose guide
and clutch cable holder.
TIP
Loosen each bolt 1/4 of a turn at a time and af-
ter all the bolts are loosened, remove them.
b. Remove the right crankcase
TIP
• Place the crankcase with its left side down-
ward and split it by inserting a screwdriver tip
into the splitting slit "a" in the crankcase.
• Lift the right crankcase horizontally while light-
ly patting the case splitting slit and engine
mounting boss using a soft hammer, and
leave the crankshaft and transmission with
the left crankcase.
ECA13910
NOTICE
Use soft hammer to tap on the case half.
Tap only on reinforced portions of case. Do
not tap on gasket mating surface. Work
slowly and carefully. Make sure the case
halves separate evenly. If the cases do not
separate, check for a remaining case bolt or
fitting. Do not force.
a
c. Remove the dowel pins and O-ring.
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2. Remove:
• Balancer shaft "1"
TIP
Remove the balancer shaft with its flat side "a"
facing the crankshaft.
EAS1DX3194
CHECKING THE TIMING CHAIN, TIMING
CHAIN GUIDE, OIL STRAINER
1. Check:
• Timing chain
Stiffness Replace the camshaft sprocket,
timing chain and crankshaft sprocket as a
set.
2. Check:.
• Timing chain guide
Damage/wear
3. Check:
• Oil strainer
Obstruction
air.
Cracks/damage
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.
6-65
CRANKCASE
1
a
Replace.
Blow out with compressed
Replace.