Valve Seat Reconditioning - Honda BF135A Manual

9. VALVE SEAT RECONDITIONING

1) Thoroughly clean the combustion chambers and valve
seats to remove carbon deposits. Apply a light coat of
Prussian Blue compound or erasable felt-tipped marker ink
to the valve faces.
2) Insert the valves, and then lift them and snap them closed
against their seats several times. Be sure the valve does not
rotate on the seat. The transfered marking compound will
show any area of the seat that is not concentric.
3) Using a 45˚ cutter, remove enough material to produce a
smooth and concentric seat. Follow the Valve Seat Cutter
Manufacturer's Instructions.
Turn the cutter clockwise, never counterclockwise.
Continue to turn the cutter as you lift it from the valve seat.
TOOLS:
Cutter holder, 5.5 mm
Valve seat cutter, 45˚ 35 mm
Valve seat cutter, 45˚ 33 mm
Valve seat cutter, 32˚ 38.5 mm
Valve seat cutter, 32˚ 33 mm
Valve seat cutter, 60˚ 30 mm
Valve seat cutter, 60˚ 37.5 mm
4) Use the 30˚ – 32˚ and 60˚ cutters to narrow and adjust the
valve seat so that it contacts the middle of the valve face.
The 30˚ – 32˚ cutter removes material from the top edge.
The 60˚ cutter removes material from the bottom edge. Be
sure that the width of the finished valve seat is within
specification.
10-28
[1]
VALVE FACE
[1] VALVE SEAT CUTER
[2]
IN, 35 mm: 07780-0010400
EX, 33 mm: 07780-0010800
07781-0010101
07780-0010400
07780-0010800
07780-0012400
07780-0012900
[4]
07780-0014000
IN, 38.5 mm: 07780-0012400
07780-0014100
EX, 33 mm: 07780-0012900
[5]
CUTTER HOLDER,
5.5 mm
07781-0010101
[1]
CONTACT
TOO HIGH
[3]
CONTACT
TOO LOW
45˚
[3]
IN, 37.5 mm: 07780-0014100
EX, 30 mm: 07780-0014000
32˚
[2] OLD SEAT
WIDTH
30˚ – 32˚
[2] OLD SEAT
WIDTH
60˚
60˚