buell s1 lightning '97 Manuel
3-17
Grinding Valve Faces and Seats
After installing valve guides, valve seats must be refaced to
make them concentric with guides.
make them concentric with guides.
Valve face angle is 45
°
for both intake and exhaust valves. If a
valve refacing grinder is used, it must be adjusted exactly to
this angle. It is important to remove no more metal than is
necessary to clean up and true valve face. Install a new valve
if grinding leaves the valve edge (the margin) with a width of
less than 1/32 in. (0.8 mm). A valve with too thin a margin
does not seat normally, burns easily, may cause pre-ignition
and can also lead to valve cracking. Valves that do not clean
up quickly are probably warped or too deeply pitted to be
reused. Replace the valve if end of valve stem shows uneven
wear. After valves have been ground, handle with care to pre-
vent damage to the ground faces.
this angle. It is important to remove no more metal than is
necessary to clean up and true valve face. Install a new valve
if grinding leaves the valve edge (the margin) with a width of
less than 1/32 in. (0.8 mm). A valve with too thin a margin
does not seat normally, burns easily, may cause pre-ignition
and can also lead to valve cracking. Valves that do not clean
up quickly are probably warped or too deeply pitted to be
reused. Replace the valve if end of valve stem shows uneven
wear. After valves have been ground, handle with care to pre-
vent damage to the ground faces.
The valve seats may be refinished with cutters or grinders.
Cut seats to a 46
Cut seats to a 46
°
angle or grind seats to a 45
°
angle. Valve
seat tools and fixtures are available commercially. Seat each
valve in the same position from which it was removed.
valve in the same position from which it was removed.
The correct 3-angle valve seat angles are shown in
Use a NEWAY VALVE SEAT CUTTER (Part No. 444-HDF;
part of
NEWAY VALVE SEAT CUTTER SET, Part No. HD-
35758)
to cut the seats. Always grind valves before cutting
seats.
1.
Cut 46
°
(or grind 45
°
) valve seat angle first. Use cutting
oil to avoid chatter marks. Cut or grind only enough to
clean up the seat.
clean up the seat.
2.
Apply a small amount of lapping compound to the valve
face. Rotate valve against seat using
face. Rotate valve against seat using
VALVE LAPPING
TOOL (Part No. HD-96550-36A)
.
3.
See
Check the contact pattern on valve
face. It should be 0.040-0.062 in. (1.02-1.57 mm) wide,
and its center should be positioned 2/3 of the way toward
the outside edge of face.
and its center should be positioned 2/3 of the way toward
the outside edge of face.
4.
If valve seat pattern is too close to the stem side of valve
face, cut 60
face, cut 60
°
angle in order to raise seat. If pattern is too
close to the edge of valve face, cut 31
°
angle in order to
lower seat.
5.
After cutting either or both 31
°
or 60
°
angles to position
seat, final cut 46
°
(or grind 45
°
) seat angle to obtain
proper 0.040-0.062 in. (1.02-1.57 mm) width.
6.
Recheck valve seat width and location with lapping com-
pound as described in Step 2.
pound as described in Step 2.
7.
To achieve a smooth even finish, place a piece of 280 grit
emery paper under the cutter head and rotate cutter.
emery paper under the cutter head and rotate cutter.
Figure 3-19. Installing Shoulderless Valve Guide
Driver Handle
(Part No. HD-34740)
5692
Valve Guide Installation
Tool (Part No. HD-34741)
Tool (Part No. HD-34741)
Cylinder Head Stand
(Part No. HD-39782)
(Part No. HD-39782)
Figure 3-20. Honing Valve Guides
Figure 3-21. Valve Seat Angles
Valve Guide Brush
(Part No. HD-34751)
5695
Cylinder Head Holding
Fixture (Part No. HD-39786)
Head
Valve
46
°
Cutting
45
°
Grinding
Seat
31
°
0.040-0.062 in.
(1.02-1.57 mm)
(1.02-1.57 mm)
60
°
Margin
b0169x3x