Suzuki LT-Z400 Service Manual page 69

INITIAL SEAT CUT
• Descale and clean up the seat using the 45° cutter. Rotate the
cutter one or two turns.
• Measure the valve seat width W after every cut.
• If the valve seat is pitted or burned, use the 45° cutter to con-
dition the seat some more.
NOTE:
Cut only the minimum amount necessary from the seat to pre-
vent the possibility of the tappet shim replacement.
TOP NARROWING CUT
• If the contact area is too high on the valve, or if it is too wide,
use the 30° cutter ( for the intake side ) and the 15° cutter (for
the exhaust side) to lower and narrow the contact area.
ENGINE
45˚
Contact area too high and
too wide on face of valve
3-25
30˚
15˚