Yamaha F150B Service Manual

Also see for F150B: Owner's manual Service manual Owner's manual

7-42Cylinder head012345678910A2. Cut the surface of the valve seat with a45° cutter by turning the cutter clockwiseuntil the valve seat face has becomesmooth. NOTICE: Do not over cut thevalve seat. Make sure to turn thecutter evenly downward at a pressureof 40–50 N (4.0–5.0 kgf, 8.8–11.0 lbf) toprevent chatter marks.a Slag or rough surface3. Use a 30° cutter to adjust the contactwidth of the top edge of the valve seat.b Previous contact width4. Use a 60° cutter to adjust the contactwidth of the bottom edge of the valveseat.b Previous contact width5. Use a 45° cutter to adjust the contactwidth of the valve seat to specification.b Previous contact widthc Specified contact width6. Check the valve seat contact area of thevalve. See “Checking the valve seat” (7-41).7. If the valve seat contact area is too wideand situated in the center of the valveface, use a 30° cutter to cut the top edgeof the valve seat, and then use a 60°cutter to cut the bottom edge to centerthe area and set its width.b Previous contact width45a30b60b45bcb3060