CLUTCH
Paragraph
Description 47
Maintenance and adjustment 48
Removal of disks 49
Inspection of disks and springs 50
Installation of disks 51
Replacement of clutch release bearing 52
=47. DESCRIPTION= (fig. 21).
=a.= Clutch is of simple multiple‐dry‐disk type, having two steel disks
and three lined disks, one of which provides spring action within disk
pack to “cushion” clutch operation.
=48. MAINTENANCE AND ADJUSTMENT= (figs. 22, 23, 24, and 25).
=a.= If clutch adjustment is correctly maintained, clutch will
cause very little trouble. Ease of gear shifting and service life
of transmission gear shifter clutch dogs depend largely upon full
disengagement of the clutch. Clutch adjustment is in two parts; namely,
control linkage and spring tension. Do not adjust clutch spring tension
before correcting control adjustment.
=b. Clutch Control Linkage= (fig. 22). Operation of foot pedal,
control cable, and clutch release lever actuates the push rod through
hollow transmission shaft, disengaging or engaging clutch at will.
Correct adjustment to control cable and release lever must be made
before push rod adjustment is made.
=c. Clutch Control Adjustment= (figs. 23, 24, 25, and 26).
(1) ADJUSTING CABLE LENGTH. With clutch in fully disengaged position
(foot pedal heel down) the clutch release lever must clear the
countershaft sprocket cover stud and/or nut by 1/16 inch. Should clutch
release lever strike sprocket cover and nut, clutch push rod movement
is restricted, and clutch cannot be fully disengaged. Length of control
cable must be adjusted to obtain 1/16-inch clutch release lever and
sprocket cover stud and/or nut clearance. To lengthen or shorten clutch
control cable, cable adjustable end must be removed from foot pedal
stud (figs. 23 and 24). With foot pedal in forward (toe down) position,
remove cotter pin and washer retaining cable end. Release other end
of cable from notch in clutch release lever by pressing release lever
inward and lifting cable end out of notch. Rock the foot pedal to rear
(heel down) position and work cable adjustable end off foot pedal stud.
Loosen lock nut and turn cable end to right (clockwise) to shorten
cable; turn to left (counter‐clockwise) to lengthen cable. Tighten
lock nut, install cable end on foot pedal stud; install washer and
cotter pin, and install other end of cable in clutch release lever
notch.
[Illustration:
=A=—CLUTCH HUB COMPLETE, WITH LINER, BEARING, STUDS, ETC.
=B=—HUB DISK LINING.
=C=—LINING RIVET (6 USED).
=D=—PIN (7 USED).
=E=—STUD.
=F=—SPROCKET COMPLETE WITH DISK SPLINE RING.
=G=—LINED DISKS (2 USED).
=H=—PLAIN STEEL DISKS (2 USED).
=J=—SPRUNG STEEL DISK WITH ONE LINING.
=K=—RELEASING DISK (WITH PUSH ROD ADJUSTING SCREW AND
ADJUSTING SCREW).
=L=—CLUTCH SPRINGS (10 USED).
=M=—STUD NUT LOCKING WASHER (3 USED).
=N=—STUD NUT (3 USED).
=O=—SPRING COMPRESSION COLLAR.
=P=—PUSH ROD ADJUSTING SCREW.
=Q=—ADJUSTING SCREW LOCK NUT.
=R=—RETAINING PLATE LOCK RING (3 USED).
=S=—BEARING RETAINING PLATE.
=T=—60 7/32-INCH STEEL BALLS.
=U=—BALL BEARING RETAINER.
RA PD 310218
_Figure 21—Clutch, Disassembled_]
[Illustration: RA PD 310219
_Figure 22—Clutch Control Linkage_]
[Illustration: RA PD 310220
_Figure 23—Clutch Lever and Stud Nut Clearance_]
[Illustration: RA PD 310221
_Figure 24—Control Cable Length Adjustment_]
[Illustration: RA PD 315715
_Figure 25—Clutch Adjustments_]
(2) ADJUSTING CLEARANCE OF CLUTCH RELEASE LEVER AND PUSH ROD (fig. 25).
With clutch release lever and sprocket cover stud clearance correctly
adjusted (step (1) above), clutch release lever must have between
1/8-inch and 1/4-inch free play at end where control cable engages lever
notch (fig. 25). This free play ensures a fully engaged clutch without
pressure on clutch release bearing. Adjustment is made by means of push
rod adjusting screw located in clutch outer disk. Remove two screws
which secure inspection hole cover to chain guard (fig. 25). If clutch
release lever has less than 1/8-inch free play at end of cable, loosen
push rod adjusting screw lock nut and turn push rod adjusting screw to
the left (counter‐clockwise) to increase amount of free play. If clutch
release lever has more than 1/4-inch free play at end of cable, turn
adjusting screw to the right (clockwise) to decrease amount of free
play. Tighten lock nut after correct adjustment is obtained. Replace
inspection hole cover. CAUTION: _If end of clutch release lever has no
free play as explained above, clutch will not hold when fully engaged.
If too much free play is allowed, clutch will drag when disengaged;
consequently, transmission gears will shift hard, clash, and eventually
become damaged._
[Illustration: RA PD 310223
_Figure 26—Adjusting Clutch Spring Tension_]
=d. Adjusting Clutch Spring Tension= (fig. 26). If clutch slips (does
not hold when starting engine or with vehicle in operation) after
controls have been correctly adjusted (step =c= (1) and (3) above),
spring tension must be increased. NOTE: _Do not increase spring tension
any more than actually required to make clutch hold._
(1) Remove front outer chain guard (par. 102).
(2) Bend down lock lips to free the three clutch adjusting nuts.
(3) Turning nuts to right (clockwise) increases clutch spring tension.
Tighten (turn to right) all three adjusting nuts, one‐half turn at a
time, until clutch holds. Test clutch after each half‐turn of the
three adjusting nuts by cranking engine. Usually a clutch that holds
without any noticeable slippage when cranking engine, also holds on the
road.
(4) After clutch spring tension adjustment is made, bend up nut lock
lips to secure adjusting nuts. Replace any broken or badly damaged
locks.
(5) When a new clutch is originally assembled and adjusted, the
distance from the inner edge of shoulder on spring collar to face of
outer (releasing) disk is 1-3/32 inches (fig. 27). In any case, do
not tighten the three adjusting nuts to the point where inner edge
of shoulder of spring collar is closer than ⅞ inch to face of outer
(releasing) disk. If compressed more, clutch probably cannot be fully
disengaged.
[Illustration: RA PD 310224
_Figure 27—Measuring Distance Between Spring Collar and Disk_]
(7) If clutch still does not hold, after correct control and spring
tension adjustments have been made, clutch “pack” assembly must be
replaced (par. 49).
(8) After making clutch spring tension adjustment, replace outer front
chain guard (par. 102).
49. REMOVAL OF DISKS (figs. 28, 29, and 30).
=a.= Clutch disks can be removed for inspection, cleaning, and/or
replacing. Springs can be removed for checking and/or replacing
without disturbing sprocket, which is integral with clutch shell. It is
advisable to remove releasing (outer) disk, springs, and collar as an
assembly because it is difficult to correctly aline, hold in place, and
reassemble springs in this unit. If springs show signs of overheating,
and appear to be “set,” they should be removed, measured, and replaced
if necessary (par. 50).
[Illustration: RA PD 315716
_Figure 28—Removing Spring and Outer Disk Assembly_]
(1) Remove outer front chain guard (par. 102).
(2) Remove push rod adjusting screw lock nut. Place a large flat
washer, approximately 1/8-inch thick, 1-3/4-inch in diameter with
a 3/8-inch center hole, over push rod adjusting screw, and replace
adjusting screw lock nut just removed (fig. 28). Tighten adjusting
screw lock nut against large washer until the three clutch spring
adjusting nuts are free. Bend nut lock down, remove the three adjusting
nuts, and withdraw releasing (outer) disk and spring assembly as one
unit. Remaining lined and plain steel disks can now be removed from
sprocket and clutch shell unit without further disassembly (fig. 30).
NOTE: _At time lined and plain disks are removed from shell, observe
relative position of each disk in order of correct assembly._
50. INSPECTION OF DISKS AND SPRINGS.
=a. Worn Disk Liners.= When disk liners are worn down flush (or
nearly flush) with rivet heads, disk and liner assembly must be
replaced.
[Illustration: RA PD 315717
_Figure 29—Outer Assembly Removed, Exposing Clutch Disks_]
[Illustration: RA PD 315718
_Figure 30—Clutch Disks, Removed_]
=b. Loose Liner Rivets.= If disk liner rivets are loose, replace disk
and liner assembly with like assembly in new or good order.
=c. Oil‐soaked Disk Liners.= If lined disks are not badly worn, but
are oil‐soaked, wash them thoroughly in clean gasoline and dry with air
or heat.
=d. Shrunken or Weak Springs.= If clutch has been badly overheated
as a result of slippage, springs may be found in shrunken or weakened
condition. Assuming disk liners are not badly worn, weakened springs
are indicated when the three spring tension nuts have been tightened
to make the clutch hold until the distance between spring collar and
releasing (outer) disk is ⅞ inch. If shrunken or weak springs are
suspected, remove them for inspection.
(1) To remove springs, remove push rod adjusting screw lock nut,
freeing spring collar and the 10 springs from the releasing (outer)
disk assembly.
(2) Measure springs for free length. Free length of new clutch springs
is approximately 1-1/2 inches (they may vary plus or minus 1/32 inch).
Old springs found to be shrunk 1/8 inch (total free length of spring
is 1-3/8 inch or less) must be replaced with new springs. NOTE: _Before
replacing springs, select 10 springs that do not vary more than 1/32
inch to make up the assembly._
(3) ASSEMBLING RELEASING DISK, SPRINGS, AND SPRING COLLAR. Place the
10 springs upright on releasing disk to centrally locate each of the
10 stud holes. Place spring collar (flanged edge down) over ends of
springs, locating the collar plate “dimples” in ends of 7 of the
springs. Place the large washer over push rod adjusting screw; tighten
adjusting screw nut, and compress springs lightly. Turn assembly over
and observe alinement of springs and disk holes. If necessary, insert
a 3/8-inch rod through holes to aline springs. Tighten down adjusting
screw nut; assembly is now ready for complete clutch assembly.
51. INSTALLATION OF DISKS (figs. 30, 29, and 28).
=a.= It is important when assembling a clutch to start with a lined
disk. Install the two steel disks so that the antirattle devices are
staggered on splines in the shell, and the “sprung” disk (lined on one
side) is the last of the pack, its lined side facing the steel disk.
Before installing disks, see that bearing retaining plate lock rings
(“R,” fig. 21) are in place on the short studs, and are tight against
the retaining plate. This is to prevent noise in the clutch.
(1) Install one of the two lined disks on clutch hub studs first.
(2) Next, engage one of the two steel disks with the splines within the
clutch shell, with side stamped “OUT” facing outward.
(3) Install the remaining lined disk on the clutch hub studs.
(4) Engage remaining steel disk with shell splines with “OUT” side
facing outward.
(5) Install “sprung” (one side lined) steel disk, lined side inward, on
clutch hub studs.
(6) It will be noted that the three long, threaded‐end, clutch hub
studs are not spaced an equal distance apart. It will also be noted
that the three holes (keyhole shaped) in the spring collar are not
spaced equidistantly. Therefore, when installing releasing disk and
spring assembly on clutch hub studs, the three threaded studs and holes
in spring collar must be alined. Install assembly on studs, replace
the three nut locks, replace the three adjusting nuts, and tighten all
three evenly until the distance between shoulder of spring collar and
face of releasing disk is 1-1/32 inch (fig. 27).
(7) Remove the large washer and replace push rod adjusting screw lock
nut. Do not attempt adjustment of clutch release lever and push rod
adjusting screw until outer front chain guard and footboard have been
installed.
[Illustration: RA PD 315719
_Figure 31—Removing Clutch Releasing Bearing Assembly_]
(8) Install outer front chain guard (par. 102).
(9) Check controls and clutch adjustment. If necessary, correct
according to paragraph 48.
52. REPLACEMENT OF CLUTCH RELEASE BEARING (fig. 31).
=a.= Clutch release lever acts against a thrust bearing and push rod
assembly which actuates clutch releasing disk.
=b. Remove Clutch Release Bearing.= Engage clutch fully (foot pedal
toe down) and disengage clutch control cable end from slotted end of
clutch release lever.
(1) Loosen rear chain guard by removing cap screw which retains rear
chain oil pipe and secures front end of rear drive chain guard to
transmission countershaft sprocket cover.
(2) Remove the four nuts which secure sprocket cover to transmission.
(3) Remove filler plug.
(4) Hold down starter crank with screwdriver.
(5) Remove sprocket cover and clutch release lever assembly. It may be
necessary to pry cover off studs. With cover removed, clutch release
bearing is exposed.
(6) Withdraw clutch release bearing and push rod assembly from
transmission shaft.
=c. Install Clutch Release Bearing.=
(1) Insert push rod with clutch release bearing assembly into
transmission shaft hole, as far as rod will go. See that bearing is
clean and well greased.
(2) Install sprocket cover. Securely tighten the four nuts.
(3) Install cap screw which secures rear chain guard end and chain
oiler pipe clamp to sprocket cover.
(4) Engage clutch control cable end in slotted end of clutch release
lever.
(5) Check clutch release lever for free play at end of cable.