Yamaha MZ250, Руководство по обслуживанию

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3-30
ENG
VALVE
VALVE LAPPING
1. Apply a coarse lapping compound evenly
on the valve face. Lap the valve by tap-
ping and rotating the valve lapper
1
clockwise and counterclockwise.
2. Clean off all of the lapping compound
from the valve face and valve seat. Apply
fine lapping compound on the valve face
and lap the valve as described in step 1.
3. Once the contacting surface of the valve
face is polished and becomes shiny,
apply mechanic’s blueing dye (Dykem) to
make sure that there are traces of even
contact in the center of the valve face.
1
6. Remove carbon deposits on the valve
face
a
and valve seat.
9
Valve face contact seat width
b
9
Valve margin thickness
c
Apply a small amount of coarse
mechanic’s blueing dye (Dykem) to the
valve seat.
Press the valve through the valve guide
and onto the valve seat to make a clear
impression.
9
Valve margin thickness
Out of specification
→
Replace.
9
Valve face contact width
Out of specification
→
Replace.
Valve seat width:
Refer to “SPECIFICATIONS” in
the Supplementary service
manual.
Valve margin thickness:
Refer to “SPECIFICATIONS” in
the Supplementary service
manual.
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