Yamaha LIT-11616-12-01 Motorcycle User Manual


 
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ENG
INSPECTION AND REPAIR
Press the valve through the valve guide
and onto the valve seat to make a clear
pattern.
Remove the valve from the cylinder head.
Measure the valve seat width a.
When the valve seat and valve face make
contact, bluing will be applied to the valve
face.
If the valve seat width is too wide, too nar-
row, or seat has not centered. The valve
seat must be refaced.
*********************************
Valve seat width Limit
Intake
0.9 ~ 1.1 mm
(0.035 ~ 0.043 in)
1.6 mm
(0.063 in)
Exhaust
4.Reface:
Valve seat
Use 30˚, 45˚ and 60˚ Valve Seat Cutter.
CAUTION:
Remove just enough material to achieve
satisfactory seat. When twisting cutter,
keep an even downward pressure to pre-
vent chatter marks.
*********************************
Valve seat refacing steps:
Å Valve face indicates that valve seat is cen-
tered on valve face but is too wide.
Valve seat cutter set:
P/N. YM-91043-B
Cut sections as follows
Section Cutter
A 30˚
B 45˚
C 60˚
Valve seat cutter set Desired result
Use
lightly
30˚ cutter To reduce valve seat
width to 1.0 mm
(0.04 in)
60˚ cutter
Å
4