Honda XL350R 1984 Shop Manual page 83

Using a 32 degree cutter, remove 1/ 4 of the existing
valve seat material.
Using a 60 degree cutter, remove the bottom 1/4 of
the old seat.
Using a 45 degree cutter, cut the seat to the proper
width.
NOTE
Make sure that aU pitting and irregularities
are removed . Refinish if necessary ,
CYLINDER HEADIVALVES
1.2-1.4
mm
(0,05- 0.06
in)
6-15