hsr-benelli S-series Service Manual page 53

smoothing operation on the face and the seat of the
valve.
Smooth:
• the face of the valve
• the seat of the valve
NOTE:
After having changed the cylinder head or the valve
and the relative guide, it will be necessary to smooth
the seat and face of the valve.
Apply a coarse grained paste (a) for smoothing on the
face of the valve.
ATTENTION:
Do not allow the smoothing paste to enter into the
space between the stem of the valve and the guide.
Apply disulfide of molybdenum to the stem of the valve.
Insert the valve into the cylinder head.
Rotate the valve until its face and seat shine uniformly,
Then remove the smoothing paste.
NOTE:
To obtain optimum smoothing results, strike the seat
of the valve lightly while turning it forwards and
backwards in your hands.
Apply a fine grained paste to the face of the valve and
repeat the above operations.
Completely eliminate the smoothing paste from the face and
the seat of the valve at the end of each operation.
Apply the tincture of bluing (b) on the face of the valve.
Install the valve in the cylinder head.
Press the valve through the valve guide and on the valve
seat to leave a clear trace.
ver.2009_03 Page 53/215