TM 5-4940-228-14
NOTE
crankshaft (49), lift key (29) from crankshaft (49).
You should follow disassembly pro-
cedure only enough to get to damaged
parts. For example, if valves require
servicing, follow procedure until
valves are removed.
a. Remove pulsation tank (4) by unscrewing four
bolts (3).
b. Both heads (15) can now be removed by un-
screwing four short bolts (13) and two long bolts
(10) from each side. Washer (11) will be removed
with long bolt (10) (Fig. 9-l).
c. Both heads (15) can be further disassembled
as follows:
(1) Remove three screws (5) which allow you
to take off filter retainer (6), outer filter (7), inner
filter (8) and screen (9).
(2) (Fig. 9-2) Remove five bolts (12a), lift off
cover (12 b), remove gasket (12c) and lift off body
(12d).
(3) Push both pistons (12e) from body (12d).
Remove four O-Rings (12f). Both pins (12g) and
both springs (12h) are loose and can be lifted out of
head.
d. (Fig. 9-1) Lift off gasket (16), valve assembly
(17) and gasket (18).
e. Both valve assemblies (17) can be further dis-
assembled as follows:
(1) Tap out two roll pins (17d) which hold the
assembly together.
(2) Top plate (17a) can now be disassembled
by unscrewing four screws (17b) and removing two
intake valves (17c).
(3) Bottom plate (17g) can be disassembled by
removing four screws (17h) and removing two dis-
charge valves (17i).
f. (Fig. 9-1) Remove cylinders (21) by removing
four each nuts (19) and washers (20). Lift off cylin-
der (21) and gasket (22).
g. Remove four pistons (25) by removing two
pieces of lock wire (23) from each piston (25). Hold
bottom part of piston (25) while removing two bolts
(24) so parts do not fall into crankcase (54).
h. (Fig. 9-4) To disassemble piston (25) remove
two piston pin plugs (25a), push piston pin (25b)
thru piston (25g) and remove four rings (25c).
i. (Fig. 9-1) Remove pulley (28) by unscrewing
two bolts (27) from two nuts (26). Slide pulley from
j. Pull dipstick (26) from crankcase, O-Ring (39)
can now be removed.
h. Remove plug (34), unscrew coupling (35), un-
screw nipple (36) and unscrew elbow (29) from
crankcase (54).
l. Remove two breather caps (30), two springs
(31), two valves (32), and two seats (33) from front
carrier (45). Remove five bolts (40) and pull rear
carrier (41) from crankcase (54). Slide crankshaft
(46) out of crankcase (54).
m. Remove front carrier (41) by removing five
bolts (44). Gasket (46), oil seal (43) bearing cup (47)
and bearing cone (48) can now be removed.
9-4. Cleaning and Inspection.
Clean all parts with a petroleum based solvent
such as kerosene or diesel fuel. Inspect parts for
damage or excessive wear. The following is a list of
tolerances:
Crankshaft journals . . . . . . . . . 1.500-1.495 in
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
(3.810-3.797 cm)
Connecting rod
Crankshaft end . . . . . . . . . . . . . . . . 1.5018-1.5025 in
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
(3.814-3.816 cm)
Piston pin end . . . . . . . . . . . . . . . . . . 0.626-0.630 in
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
(1.590-1.600 cm)
Cylinder bore . . . . . . . . . . . . . . . . . . . . . . 2.625-2.630 in
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
(6.667-6.680 cm)
Piston pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.625-0.622 in
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
(1.587-1.580 cm)
Piston pin hole . . . . . . . . . . . . . . . . . . . 0.625-0.630 in
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
(1.587-1.600 cm)
Piston diameter . . . . . . . . . . . . . . . . . 2.619-2.615 in
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
(6.652-6.642 cm)
9-5. Reassembly.
a. (Fig. 9-1) Assemble two seats (33), two valves
(32), two springs (31) and two breather cups (30)
into rear carrier (41). Press bearing cup (47) and oil
seal (43) into rear carrier (41). Using a new gasket
(42) and five bolts (40), attach rear carrier (41) to
crankcase (51).
b. Install a bearing cone (48) on each end of
crankshaft (49). Slide crankshaft (49) thru crank-
case (51) (slotted shaft end first) and thru rear car-
rier (41). Hold crankshaft centered while installing
bearing cup (47), gasket (46) and front carrier (45).
Screw in five bolts (44). Torque five bolts (40) and
five bolts (44) to 225 in Ibs (40,185 gr cm).
9-3
