VALVE SEAT INSPECTION/REPAIR

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1. Measure the contact width of the valve face and the valve seat using the valve lapping compound.

  • If it is not within the specification, resurface the valve seat using the 45° valve seat cutter.

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  Standard valve seat contact width

  IN: 1.2—1.6 mm {0.048—0.062 in}
  EX: 1.2—1.6 mm {0.048—0.062 in}

2. Verify that the area where the valve seat contacts the valve face is centered.

  • If the seating position is too high, resurface the valve seat using a 70° (IN) 65° (EX) valve seat cutter and a 45° valve seat cutter.

  • If the seating position is too far inside, correct the valve seat using a 30° (IN) cutter, and a 45° cutter.

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  Valve seat angle

  IN: 45°
  EX: 45°

3. Inspect the valve seat for sinkage. Measure the protruding length (dimension L) of the valve stem using a valve of standard length.

  • If it is not within the specification, replace the cylinder head.

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  Standard valve seat sinkage amount (Dimension L)

  IN : 40.64—42.24 mm {1.600—1.662 in}
  EX :40.50—42.10 mm {1.595—1.657 in}