ENGINE 3-37 VALVE SEAT SERVICING • The valve seats 1 for both the intake valve 2 and exhaust valve 3 are machined to four different angles. The seat con- tact surface is cut at 45°. 60˚ 60˚ 30˚ 15˚ INTAKE EXHAUST 45˚ 45˚ 15° N-121 30° N-126 45° N-122 N-122 60° N-111 N-111 09916-21111: Valve seat cutter set 09916-20630: Valve seat cutter (N-126) 09916-20640: Solid pilot (N-100-4.5) 45˚ NOTE: 15˚ The valve seat cutters (N-121), (N-122) and (N-111) are included in the valve seat cutter set (09916-21111).  30˚ 60˚ The valve seat contact area must be inspected after each cut. E • When installing the solid pilot 1, rotate it slightly. Seat the pilot snugly. Install the 45° cutter, attachment and T-handle. L P SAM INITIAL SEAT CUT • Using the 45° cutter, descale and clean up the seat. Rotate the cutter one or two turns. • Measure the valve seat width W after every cut. 45˚