buell s1 lightning '97 Manual

1

8.

 Wipe valve seats and valve faces clean.

Measure valve stem protrusion. If valve stem protrudes
more than 2.034 in. (51.66 mm), replace valve seat or
cylinder head. If valve stem protrusion is within the
acceptable range, valves and seats are ready for lapping.

Replacing a valve seat is a complex operation requiring spe-
cial equipment. If the seat is loose or is not fully seated in the
head, then seat movement will prevent the proper transfer of
heat from the valve. The seat surface must be flush with (or
below) the head surface. See 

 for valve

seat-to-cylinder head fit.

To remove the old seat, lay a bead of weld material around
the inside diameter of the seat. This will shrink the seat out-
side diameter and provide a surface for driving the seat out
the port side.

NOTE

If valve faces and seats have been smoothly and accurately
refaced, very little lapping will be required to complete the
seating operation.

1.

See 

 Apply a light coat of fine lapping com-

pound to valve face. Insert valve in guide. Position one
rubber cup end of 

shown, apply only very light pressure against valve head,
and rotate lapping tool and valve alternately clockwise
and counterclockwise a few times.

2.

Lift valve and rotate it about 1/3 of a turn clockwise.
Repeat lapping procedure in Step 1.

3.

Repeat Step 2. Then, remove valve.

4.

Wash valve face and seat; dry with a new, clean cloth or
towel.

5.

If inspection shows an unbroken lapped finish of uniform
width around both valve and seat, valve is well seated. If
lapped finish is not complete, further lapping (or grinding
and lapping) is necessary.

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