Suzuki DF2.5 Service Manual page 77

the valve stem end face for and wear. If or
the valve stem end may be resurfaced.
of stem has been worn away, the
mm
exceeds the service the valve.
the valve head radial runout.
measurement exceeds the service the valve.
the thickness of the valve head.
IN, & EX, 0.5
exceeds the service replace the valve.