ENGINE 3-39 FINAL SEAT CUT • If the contact area W is too low or too narrow, use the 45° cut- ter to raise and widen the contact area. NOTE: After cutting the 15°, 30° and 60° angles, it is possible that the valve seat (45°) is too narrow. If so, re-cut the valve seat to the correct width. 45˚ • After the desired seat position and width is achieved, use the E 45° cutter very lightly to clean up any burrs caused by the pre- vious cutting operations. L  P Do not use lapping compound after the final cut is M made. The finished valve seat should have a velvety smooth finish but not a highly polished or shiny fin- A ish. This will provide a soft surface for the final seat- ing of the valve which will occur during the first few S seconds of engine operation.  The titanium valves are coated with an oxidized mem- brane treatment to resist wear but the membrane tend to be removed if lapped after valve seat servicing. NOTE: After servicing the valve seats, be sure to check the valve clear- ance after the cylinder head has been reinstalled. (2-7)