Rato R160, Service Manual

Page: 64 / 78

62
Valve seat
：
a) Thoroughly clean the combustion chambers and
valve seats to remove carbon deposits. Apply a
light coat of red lead powder or erasable color
painting to the valve faces.
Insert the valves, and then press the valve several
times forcefully. Be sure the valve does not rotate
on the seat.
The transferred marking compound will show any
area of the seat that is not concentric.
b) Using 45°cutter, remove enough material to
produce a smooth and concentric seat.
c) Turn cutter clockwise, never counterclockwise.
d) Continue turning the cutter as you lift it from the
valve seat.
Tool
：
Valve seat cutter
Use the 32°-45°cutters to narrow and adjust the valve seat so that it contacts the middle of
the valve face. The 32°cutter removes material from the
top edge (contact too high).
The 45°cutter removes material from the bottom edge
(contact too low). Be sure that the width of the finished
valve seat is within specification.
Standard Service limit
See 1-3Maintenance Standard See 1-3Maintenance Standard
d) Make a light pass with the 45°cutter to remove any possible burrs at the edges of the
seat.
VALVE
FACE
CUTTER
HOLDER
IN valve
：
32°
EN valve
：
32°
IN valve
：
45
EX valve
：
45