Seat Replacement

1. Cut the valve seat to be replaced from the inside, to thin the wall thickness. Then, remove the valve seat.





2. Rebore the valve seat hole in the cylinder head to a selected oversize valve seat diameter.
Intake seat ring hole diameters
0.3 O.S.: 34.30 - 34.33 mm (1.3504 - 1.3516 inch)
0.6 O.S.: 34.60 - 34.63 mm (1.3622 - 1.3634 inch)
Exhaust seat ring hole diameters
0.3 O.S.: 31.80 - 31.83 mm (1.2520 - 1.2531 inch)
0.6 O.S.: 32.10 - 32.13 mm (1.2638 - 1.2650 inch)
3. Before fitting the valve seat, either heat the cylinder head up to approximately 250° C (482° F) or cool the valve seat in liquid nitrogen, to prevent the cylinder head bore from galling.
4. Using a valve seat cutter, correct the valve seat to the specified width and angle.