6. CYLINDER HEAD/VALVES STRYKER 125/150 Use a 63.5° cutter to remove the lower existing valve seat material. Old Seat Width Install a 45° finish cutter and cut the seat to the proper width. Standard Seat Width: 1.0mm Inspect the valve seat contact area. If the contact area is too high on the valve, Contact too High the seat must be lowered using a 37.5° cutter. If the contact area is too low on the valve, the seat must be raised using a 63.5° cutter. Old Seat Width Refinish the seat to specifications using a 45° seat cutter. After cutting the seat, apply emery to each valve contact face and lap the valve using a lapper. 6-13