Honda BF40D Manuel D'utilisation page 130

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4) Use the 32 and 60
seat so that it contacts the middle of the valve face.
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The 32 cutter removes material from the top edge.
1
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The 60 cutter removes material from the bottom edge. Be
sure that the width of the finished valve seat is within
2
specification.
3
Valve seat width
4
5
6
7
8
5) Make a light pass with the 45° cutter to remove any
9
possible burrs at the edges of the seat.
6) After resurfacing the seats, inspect for even valve seating.
10
Apply Prussian Blue compound or erasable felt-tipped
marker ink to the valve faces. Insert the valves, and then lift
11
them and snap them closed against their seats several
times. Be sure the valve does not rotate on the seat. The
12
seating surface, as shown by the transferred marking
compound, should have good contact all the way around.
13
14
15
16
17
7) Lap the valves into their seats, using a hand valve lapper
and lapping compound (commercially available).
18
NOTICE
19
To avoid severe engine damage, be sure to remove all
lapping compound from the cylinder head before
20 assembly.
9-22
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cutters to narrow and adjust the valve
1.25 - 1.55 mm
IN/EX
(0.049 - 0.061 in)
[1]
VALVE SEAT
TOO HIGH
[2]
VALVE SEAT
TOO LOW
[1]
IN/EX: 1.25 - 1.55 mm
(0.049 - 0.061 in)
[1]
VALVE LAPPER
(Commercially
available)
130
[3]
OLD SEAT
WIDTH
o
32
[3] OLD SEAT
WIDTH
o
60