1998-2004 Honda Foreman 450 factory service manual, Page 145Get this manual
CYLINDER HEADCYLINDERPISTON Reface the seat with 45-degree cutter whenever valve guide is replaced
Use 45-degree cutter to remove any roughness or irregularities from the seat
ROUGHNESS
Use 32-degree cutter to remove the top 14 of the existing valve seat material
Use 60-degree cutter to remove the bottom 14 of the old seatRemove the cutter and inspect the area you have refaced