Separating The Crankcase; Checking The Timing Chain And Guide; Checking The Relief Valve - Yamaha YXR70FX Service Manual

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CRANKCASE
EBS00332

SEPARATING THE CRANKCASE

1. Separate:
• left crankcase
• right crankcase
M MMM M MMM M M MMM M M MMM M
a. Remove the crankcase bolts.
TIP:
_
• Loosen each bolt 1/4 of a turn at a time and
after all the bolts are loosened, remove
them.
• Loosen the bolts in numerical order (see
numbers on the illustration).
È Right crankcase
É Left crankcase
b. Remove the right crankcase.
NOTICE
_
Use a soft hammer to tap on one side of the
crankcase. Tap only on reinforced portions
of the crankcase. Do not tap on the crank-
case mating surfaces. Work slowly and
carefully. Make sure that the crankcase
halves separate evenly.
c. Remove the dowel pins.
L LLL L LLL L L LLL L L LLL L
EBS00335

CHECKING THE TIMING CHAIN AND GUIDE

1. Check:
• timing chain
Cracks/stiff → Replace the timing chain and
camshaft sprocket as a set.
2. Check:
• intake side timing chain guide
Wear/damage → Replace.

CHECKING THE RELIEF VALVE

1. Check:
• spring seat 1
• spring 2
• relief valve body 3
• relief valve 4
Damage/wear → Replace the defective
part(s).
ENG
M MMM M M MMM M MMM
L LLL L L LLL L LLL