Suzuki GN125F, Service Manual

Page: 42 / 148

E N G I N E
3-11
Place the dial gauge at right angles to the valve head,
and measure the valve head radial runout. If it measures
more the limit, replace the valve .
09900-20606: Dial gauge (1/100 mm)
09900-20701: Magnetic stand
09900-21304: V-block ( 100 mm)
Valve stem runout limit: 0.03 mm
Support the valve with “V” blocks as shown, and check its
runout with a dial gauge. The valve must be replaced if the
runout exceeds the limit.
09900-20606: Dial gauge (1/100 mm)
09900-20701: Magnetic stand
09900-21304: V-block ( 100 mm)
Valve stem runout limit: 0.05 mm
Throughly clean the the carbon deposits on the valves and
valve seat.
Coat the valve seat with Prussian Blue uniformly.
Hold the valve with valve lapper, fit the valve and tap the
coated seat with the valve face in a rotating manner in order
to obtain a clear impression contact.
The ring-like dye impression left on the valve face must be
continuous without any break.
The impression contact can be used to check the contact
surface institute, the contact position.
In addition, the width of the dye ring, which is the visualized
seat "width", must be within the specification.
If any requirement is not met, correct the valve seat by
servicing it as follow steps.
09916-10911: Valve lapper set
VALVE SEAT INSPECTION AND SERVICING
30
o
45
o
60
o
15
o
The valve seat contact area must be inspected after
each cut.
Do not use lapping compound after the final cut is
made. The finished valve seat should have a velvety
smooth finish but not a highly polished or shiny finish.
This will provide a soft surface for the final seating of
the valve which will occur during the first few seconds
of engine operation.
CAUTION
INTAKE
valve seat
60
O
45
O