TOHATSU MFS 9.9 Owner's Manual page 137

Power Unit
9. Apply thin coat of abrasive compound on the overall valve
seat contact area, and turn valve lapper (commercially
available item) while lapping valve.
Perform the work by taking care not to
allow abrasive compound to adhere to
valve stem and valve guide.
· Use finer abrasive compound to finish.
· When changing abrasive compound to finer
one, remove present one completely.
· After completion of lapping, wipe off the
compound and then clean.
10. After ending the work, remove the compound completely
from cylinder head and valve.
Check valve seat contact width c.
11.
Valve Seat Contact Width
1.0 mm (0.04 in)
17) Inspection of Locker Arm and
Locker Arm Shaft
1. Check rocker arm, rocker arm shaft and rocker arm contact
area a for wear. Replace if necessary.
Measure rocker arm inner diameter a and rocker arm shaft
2.
outer diameter c. Calculate oil clearance d (d = b - c).
Replace if out of specification.
Rocker Arm Inner Diameter b : Standard Value
13.01 mm (0.5122 in)
Rocker Arm Shaft Outer Diameter c : Standard Value
12.99 mm (0.5114 in)
Oil Clearance Between Rocker Arm Hole and Shaft d :
0.006 - 0.035 mm (0.00024 - 0.00138 in)
Functional Limit :
bReplace if b is over 13.05 mm (0.5138 in).
cReplace if c is less than 12.94 mm (0.5094 in).
dReplace if b is over 0.060 mm (0.00236 in).
5-34
CAUTION
c：Standard Value
bContact width before correction
cSpecified width
a
c
b
d = b - c
b
c
45˚
4st 9.9/15/20 2008