(12) Remove back plate (22) and gasket (23) by
removing screws (19), screws (21) and lockwashers
(13) Camshaft Bearings. The camshaft bearings
(25, 26 and 27, figure 7-21) should be replaced if
clearance to camshaft is greater than specified, bear-
ings show cracks breaks, burrs, excessive wear, or
other defects. The camshaft to bearing clearance
should be 0.0012 to 0.0037 inch. To check rear bear-
ing (25) remove expansion plug (24) at rear of crank-
b. Cleaning and Inspection. If a cam lobe has be-
come slightly scored, dress it smooth with a fine
stone. If camshaft is badly worn or scored, replace it.
(1) Press new camshaft bearings into place. See
figure 7-25 for proper placement. Press rear bear-
ing flush with bottom of expansion plug recess. Press
front bearing in flush with crankcase front surface
so oil passages are aligned. Do not attempt to ream
bearings, they are a precision type. After rear bear-
ing is installed, insert a new expansion plug in re-
cess, using sealing compound, and expand it into place
with sharp blows at its center.
(2) Install new gasket (23, figure 7-21) and back
plate (22) with screws (19 and 21) and lockwashers
(3) Refer to paragraph 7-17 and install crank-
(4) With engine laid on its side, install tappets (27,
(5) Install key (18, figure ?-21) on camshaft (15),
press on gear (17) and install retaining ring (16).
(6) Install camshaft assembly (15) in engine
making sure tappets (26) are in place on push rods.
Align timing marks on camshaft gear and crankshaft
gear (see figure 7-26). Check gear lash (see figure
(7) Install oil base per paragraph 7-10.
(8) Install crankshaft gear retaining washer (9,
figure 7-21) and retaining ring (8) on the crankshaft.
(9) Refer to paragraph 7-9 and install rocker
(10) Refer to paragraph 7-18 and install fuel
Expansion plug must not protrude from rear
face of crankcase.
(11) Refer to paragraph 7-14 and install gear
Figure 7-25. Camshaft Bearing Installation