Yamaha F40B - Checking the Rocker Arm and Rocker Arm Shaft; Checking the Camshaft

POWR
Power unit
5-35 67C3K11
9. If the valve seat contact area is too nar-
row and situated near the bottom edge of
the valve face, use a 60° cutter to cut the
bottom edge of the valve seat, and then
use a 45° cutter to center the area and
set its width.
b Previous contact width
10. After refacing the valve seat to the speci-
fied contact width, apply a thin, even
layer of lapping compound onto the valve
seat, and then lap the valve using a valve
lapper.
CAUTION:
Do not get the lapping compound on the
valve stem and valve guide.
11. After every lapping procedure, be sure to
clean off any remaining lapping com-
pound from the cylinder head and the
valve.
12. Check the valve seat contact area of the
valve again.
NOTE:
To check the valve seat contact area, see
“Checking the valve seat” (5-32).
Checking the rocker arm and rocker
arm shaft
1. Check the rocker arms, rocker arm shaft,
and contact surface a of each rocker
arm. Replace if worn.
2. Measure the rocker arm inside diameter
b and rocker arm shaft outside diameter
c. Replace if out of specification.
Checking the camshaft
1. Measure the cam lobe height a and
width b. Replace if out of specification.
S6AG5J50J
60˚
b
S67C5098
Rocker arm inside diameter b:
16.000–16.018 mm
(0.6299–0.6306 in)
Rocker arm shaft outside
diameter c:
15.971–15.991 mm
(0.6288–0.6296 in)
S67C5099
b
c
a
b