Honda BF40D Manual page 120

• VALVE GUIDE I.D.
1) Before measuring the valve guide I.D., ream the valve
guides to remove any carbon deposits using the special
1
tool.
NOTICE
2
Turn the special tool (valve guide reamer, 5.510 mm)
clockwise; never turn it counterclockwise. Continue to turn
3
it clockwise as you lift it from the valve guide.
4
TOOL:
Valve guide reamer, 5.510 mm
5
2) Measure and record each valve guide I.D.
6
7
IN/EX
8
3) If the measurement exceeds the service limit, replace the
valve guide with a new one.
9
• Check the valve stem-to-valve guide clearance after
10
replacing the valve guide.
• VALVE STEM-TO-VALVE GUIDE CLEARANCE
11
Calculate the gap between the valve stem O.D. and the valve
guide I.D.
12
13
IN
14
EX
15
If the stem-to-guide clearance exceeds the service limit,
16
replace the valve and the valve guide as a set (P. 9-19).
17
• VALVE SEAT WIDTH
Measure the valve seat width.
18
19
IN/EX
20
If the valve seat width is too wide or narrow, or if the valve seat
is too high or low, recondition the valve seat (P. 9-21).
9-17
07984-2000001
Standard Service limit
5.500 - 5.512 mm 5.530 mm
(0.2165 - 0.2170 in) (0.2177 in)
Standard Service limit
0.010 - 0.030 mm 0.060 mm
(0.0004 - 0.0012 in) (0.0024 in)
0.030 - 0.050 mm 0.100 mm
(0.0012 - 0.0020 in) (0.0039 in)
Standard Service limit
1.25 - 1.55 mm 2.00 mm
(0.049 - 0.061 in) (0.079 in)
[1]
VALVE GUIDE
REAMER, 5.510 mm
07984-2000001
[1]
VALVE
SEAT
TOO
LOW
[2]
VALVE
SEAT
TOO
HIGH
120
[3]
VALVE SEAT
WIDTH