Buell 2002 X1 Handbook page 150

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Grinding Valve Faces and Seats
After installing valve guides, reface valve seats to 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.
The valve seats may be refinished with cutters or grinders.
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.
The correct 3-angle valve seat angles are shown in
21. Use NEWAY VALVE SEAT CUTTER SET (Part No. HD-
35758A) to cut the seats. See
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.
2. Apply a small amount of lapping compound to the valve
face. Rotate valve against seat using VALVE LAPPING
TOOL (Part No. HD-96550-36A).
3. See Figure 3-21. Check the contact pattern on valve
face. It should be 0.040-0.062 in. (1.016-1.575 mm)
wide, 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 a 60° angle in order to raise seat. If pattern is
too close to the edge of valve face, cut a 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. (1.016-1.575 mm) width.
6. Recheck valve seat width and location with lapping com-
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.
3-18
Figure 3-
Figure 3-22. Always grind
b0169x3x
Head
Seat
0.040-0.062 in.
(1.016-1.575 mm)
31°
46° Cutting
45° Grinding
Figure 3-21. Valve Seat Angles
hd35758
Figure 3-22. Neway Valve Seat Cutter Set
(Part No. HD-35758A)
Table 3-4. Neway Valve Seat Cutters
VALVE SEAT 60° CUTTER
Exhaust Part No. 205
Intake Part No. 293
60°
Valve
Margin
31° AND 46°
CUTTERS
Part No. 622
Part No. 642
2002 Buell X1: Engine