Overhauling Transmission And Clutch

Removing Transmission From Chassis

A. Lower rear end of bottom skid plate. In some cases it will be found necessary to remove only the two rear mounting bolts; in other cases a U-clamp holding skid plate to front frame tube will have to be removed.

B. Remove left footboard, sidebar and clutch pedal assembly in one unit. Release cable must first be disconnected from clutch footpedal by removing cotter pin and washer.

C. Remove oil bath air cleaner and mounting plate; this requires loosening hose clamp at carburetor hose connection fitting and removing the three bolts attaching mounting plate to frame.

D. Remove outer front chain guard.

E. Remove engine sprocket, using manufacturer's wrench number 12731-29. It will be necessary to strike wrench with a hammer to loosen nut. Remove sprocket from taper by giving flat surface near outer edge a light but sharp rap with a hammer, being careful not to strike teeth.

F. Free inner front chain guard by removing the two mounting screws.

G. Remove tool box from mounting bracket by removing the two mounting bolts from inside of box; then remove mounting bracket from frame.

H. Remove brake rear rod.

I. Remove rear chain.

J. Remove rear chain guard.

K. Remove battery box as follows: Disconnect battery terminal wires and remove battery. Loosen two nuts securing rear safety guard center connection to mounting studs. Unscrew mounting studs to free plate clamping battery box bracket to frame. Remove battery box front bolt and two rear bottom bolts. Remove battery box from left side of frame.

L. Remove clutch release cable and tube.

M. Remove shifter rod.

N. Remove three bottom mounting stud nuts and lift transmission to permit removal of front chain adjusting screw.

O. Loosen U-bolts on ignition coil and swing coil as far as possible toward the front.

P. Remove transmission and clutch assembly as follows: Lift unit to free mounting studs from frame slots, rotate top of transmission backward about a guarter turn and remove from left side of frame.

Disassembling Transmission

A: Disassemble and remove clutch as described under "Disassembling Clutch," Page 22, and "Removing Clutch Hub," Page 67.

B. Remove starter crank.

C. Remove sprocket cover.

D. Remove top inspection cover (Item 76).

E. Remove shifter cam (Item 62) by unscrewing lock screw (Item 64) and pulling out shifter cam shaft (Item 63).

F. Remove shifter fork assemblies by drifting shaft (Item 59) out through hole in transmission side cover.

Caution: Bear in mind that shifter fork assemblies are not interchangeable; note exact arrangement of parts before disassembling. This precaution can save needless gauging and adjusting when reassembling.

G. Remove sprocket (Item 42) using manufacturer's wrench number 12731-29. It will be necessary to strike wrench with a hammer to loosen nut (Item 44). Remove sprocket from taper by giving it a light but sharp rap with a hammer, near outer edge, being careful not to strike teeth.

H. Remove transmission side cover (Item 40); all gears, shafts, etc., are now free to be removed from open side of case.

Note: Do not remove clutch gear oil seal and bearing retaining washer (Items 70 and 71—1941 and later only) unless inspection shows them damaged or worn.

Removing Clutch Hub

Remove clutch hub nut (Item 74). On 1940 models use manufacturer's wrench number 12745-26 with adapter number 12745-26A; on 1941 and later models use wrench number 12745-41.

1940 model: Clutch hub can be removed from taper by giving it a light but sharp rap with a hammer and soft punch, striking close to center but being careful not to strike bearing.

1941 and later models: Clutch hub is a press fit on splined end of clutch gear. Puller number 12022-41 is needed to remove it.

Inspection of Parts

Inspect all parts and determine which must be renewed. Check all gears for extent of tooth wear; also inspect all bushings and bearing races.

Give especially close attention to possibly battered or rounded condition of engaging dogs on shifter clutches and clutch gear and engaging slots in other gears. This condition results from shifting abuses or possibly from poorly adjusted clutch that does not release fully.

Damaged engaging dogs and slots try to creep out of engagement under steady driving load. This creeping action develops tremendous side pressure that finally results in serious damage to shifting mechanism and all thrust points along the mainshaft assembly. Therefore, in doing a thorough and dependable transmission overhaul, it is of prime importance that all gears and shifter clutches with badly rounded engaging dogs and slots be replaced with new.

Installing Clutch Gear

A. Assuming that oil seal (Item 71) and bearing retaining washer (Item 70) are already assembled in case, install roller bearing end washer (Item 17) in roller race next. Assemble rollers (Item 16) in roller race after applying sufficient grease to race to hold rollers in place.

B. Insert oil seal tool (manufacturer's tool number 12747-41) through oil seal from the outside so that it will be in place to meet clutch gear when it is inserted through bearing from the inside. It is necessary that this oil seal tool be used to facilitate assembly and avoid damaging oil seal. Assemble thrust bearing race (Item 14) and retainer and balls (Item 15) on clutch gear. Now insert clutch gear through bearing from inside of case. Be sure end of gear is engaged with oil seal tool before pushing it through seal.

Adjusting Mainshaft Endplay

A. Install mainshaft in case with mainshaft spacer (Item 24), thrust washer (Item 35) and spacing collar (Item 36) in place.

B. Install roller bearings (Item 37) in side cover bearing race, holding them in place by means of light coat of grease.

C. Install side cover and gasket on transmission case. In checking endplay, it is important to tighten cover screws and stud nuts just^as tight as in final assembly; otherwise endplay in final assembly will not be the same as this check shows. Check endplay as indicated in Illustration 53; it should be .003" to .005". Increase or decrease endplay as necessary by fitting mainshaft spacer (Item 24) of required thickness.

D. After correct mainshaft endplay has been established, remove mainshaft from case and set aside spacer washer selected, to be sure it goes into final assembly.

Adjusting Endplay of Low and Second Gears Between Retaining Bracket and Transmission Side Cover

A. Assemble only the following parts on main-shaft: From left (clutch) end—low gear end thrust washer (Item 32), low gear (Item 31), endplay adjusting washer (Item 30), second gear (Item 29), main-shaft spacer (Item 24); from right (sprocket) end— thrust washer (Item 35) and spacing collar (Item 36).

B. Install roller bearings in side cover and install gasket and cover on case. Tighten cover just as tight as in final assembly.

C. Check endplay of low and second gears between sidecover (Item 40) and second gear retaining bracket (Item 26), as indicated in Illustration 53. Measure by means of thickness gauge inserted between second gear retaining bracket and second gear. Endplay should be .005" to .007". Adjust as necessary by fitting endplay adjusting washer (Item 30) of required thickness.

After correct endplay adjustment has been attained, remove mainshaft assembly from transmission. Be sure selected endplay washer remains with the assembly.

Assembling Transmission

After mainshaft spacer (Item 24) and endplay adjusting washer (Item 30) in their required thicknesses have been selected, complete assembly of transmission can proceed, reversing order of disassembly.

If new shifter clutches (Items 25 and 34) are required, see that they fit free on mainshaft and slide on shaft splines without binding. Shifting will be difficult unless these parts work freely.

When assembling shifter cam, two things must be watched very closely: First, shifter finger rollers must be in place on shifter fingers; second, shifter cam gear and shifter lever gear must be correctly timed. Small gear has one tooth chamfered at end. This tooth must engage with space marked "3" between teeth of large gear. See Illustration 54.

Adjusting Shifter Clutches

With shifter cam (Item 62) in neutral position and highest points on driving dogs overlapping about Va" (See Illustration 54), the following clearances should exist:

Shifter fork to low gear—

1941 and later 283" to .288"

Shifter clutch to clutch gear—

1941 and later 053" to .058"

Suitable strips of metal dressed down to the above thicknesses will serve as gauges for these adjustments.

Relative adjustment between shifter fingers (Items 48 and 53) and shifter forks (Items 46 and 55) is determined by spacing shims (Items 47 and 54). By increasing or reducing number of these shims between shifter forks and shifter fingers (Items 48 and 53) a corresponding change is effected in clearance of shifter clutches. These adjusting shims are .007"

and .014" in thickness. Transfer shims as necessary to properly locate clutches. Reassemble shifter fork assemblies to transmission and recheck clearances.

Before installing transmission inspection (top) cover, pour about 3/* pint of oil (same grade as used in engine) into case; 1940 and earlier holds Vi pint.

Installing Clutch Hub

Clutch hub and clutch may be installed either before or after transmission is installed in frame.

1941 and later clutch hub is a light press fit on splined end of clutch gear. Drive hub onto splines with a hammer and a block of wood or piece of tubing of required diameter. Install lock washer (Item 73), tighten nut (Item 74) securely and lock by setting washer into one of the nut wrench slots with a punch.

If sprocket bearing (Items 80 and 81) and bearing retaining plate (Item 82) have been removed from hub, re-install them first. Bearing retaining plate is held in place against hub face by spring rings (Item 83) pushed onto three short studs and tight against

SPACER (ITEM 24) ASSEMBLED BETWEEN MAIN-SHAFT SHOULDER AND END OF CLUTCH GEAR DETERMINES MAINSHAFT ENDPLAY.

MAINSHAFT ENDPLAY .003" TO .005". ADJUST WITH SPACER (ITEM 24) OF REQUIRED THICKNESS.

SECOND GEAR RETAINING BRACKET (ITEM 26).

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