Suzuki RA410, Manual

Page: 305 / 761

Inspect valve stem end face for pitting and wear. If pitting or wear
is found there, valve stem end may be resurfaced, but not so
much as to grind off its chamfer. When it is worn so much that
its chamfer is gone, replace valve.
Seating contact width:
Create contact pattern on each valve in the usual manner, i.e.,
by giving uniform coat of marking compound to valve seat and
by rotatingly tapping seat with valve head. Valve lapper (tool
used in valve lapping) must be used.
Pattern produced on seating face of valve must be a continuous
ring without any break, and the width of pattern must be within
specified range.
6A4-46 ENGINE MECHANICAL
Standard seating width
revealed by contact pattern
In
1.80 – 2.20 mm
(0.0709 – 0.0866 in.)
revealed by contact attern
on valve face
Ex
1.65 – 2.05 mm
(0.0650 – 0.0807 in.)