Circuit Breaker Head Disassembled

Installing Circuit Breaker and Timing Ignition (O.H.V. Engine)

(1946 and Earlier Models)

Refer to Illus. 66—also see "Timing Ignition By Piston Position," Page 86.

Turn engine in direction in which it runs until tappets indicate front cylinder is on compression stroke (directly after front intake valve closes). Continue turning engine slowly until flywheel timing mark is at rear edge of inspection hole in left crank-case.

If front cylinder head is off—circuit breaker completely assembled, can be installed. Be sure ground spring is in its proper place so when cover retainer ends are inserted through holes in circuit breaker head, they also register in spring locating notches. Otherwise, spring will have no tension and the head will be loose on its base. Contact points and condenser are grounded through circuit breaker base and this spring holds the head in close contact with base, thus insuring a good ground.

First make sure mark (4) on circuit breaker head and hole (4) in circuit breaker adjusting band line up before installing circuit breaker.

Turn circuit breaker shaft counter-clockwise (to left) approximately 60° from position where mark (4)

on breaker cam lines up with fibre block on breaker lever.

Install base gasket and circuit breaker assembly, inserting shaft and shaft gear all the way down into place in gear case, with base turned so low tension wire is toward left side of engine and circuit breaker base mounting screw holes line up with holes in crankcase but do not as yet install base mounting screws.

Hold relay bracket on crankcase temporarily so mounting holes in bracket line up with holes in crankcase and stud in advance and retard lever registers in slot in bracket.

Fully advance lever (8) (turn counter-clockwise) and with relay bracket held in position, observe how closely mark (4) on breaker cam lines up with lever fibre.

If it does not line up, lift circuit breaker base and turn shaft gear so its engagement with its driving gear is changed one tooth. Check again according to breaker cam mark. Repeat this procedure until gear engagement is attained which closely aligns mark (4) and breaker lever fibre. When this has been accomplished, secure base and relay bracket with screws and lock washers.

Provided circuit breaker cam shaft gear has not been replaced and mark (4) on side of circuit breaker head and hole (4) in adjusting band are still in align ment, and breaker point gap is correctly adjusted, engine is now timed according to original factory setting. See' "Recommended Recheck of Ignition Timing," Page 83.

It iiont cylinder head is on—circuit breaker must be disassembled before it can be installed.

First make sure mark (4) on circuit breaker head and hole in circuit breaker adjusting band line up.

Install gasket and circuit breaker head tension (ground) spring on circuit breaker base assembly and insert shaft and shaft gear all the way down into place in timing gear case, trying to locate mark on small end of breaker cam in position shown in Illus. 66. Do not as yet install base mounting screws.

Install circuit breaker head and hold relay bracket on crankcase temporarily so mounting holes in bracket line up with holes in crankcase, and stud in advance and retard lever (8) registers in slot in relay bracket. Do not install cover retainer until later.

Fully advance lever (8) (turn counter-clockwise) and with relay bracket held in position, observe how closely mark (4) on breaker cam lines up with breaker lever fibre.

If it does not line up, lift circuit breaker base and turn shaft gear so its engagement with its driving gear is changed one tooth. Check again according to breaker cam mark. Repeat this procedure until gear engagement is attained which closely aligns mark (4) and breaker lever fibre. When this has been accomplished, make sure base is turned so ignition coil wire is toward left side of engine and secure base and relay bracket with screws and lock washers.

Make sure that low tension wire is allowed enough slack within circuit breaker head to be free for full advance and retard movement.

Install head on base and secure with ground spring and cover retainer. Be sure ground spring is in its proper place so when cover retainer ends are inserted through holes in circuit breaker head, they also fit into spring locating notches. Otherwise, spring will have no tension and the head will be loose on its base. Contact points and condenser are grounded through circuit breaker base and this spring holds the head in close contact with base, thus insuring a good ground.

Provided circuit breaker cam shaft gear has not been replaced and mark (4) on side of circuit breaker head and hole (4) in adjusting band are still in alignment, and breaker point gap is correctly adjusted, engine is now timed according to original factory setting. See "Recommended Recheck of Ignition Timing," Page 83.

Installing Circuit Breaker and Timing Ignition (Side Valve Engine)

(1946 and Earlier Models)

Refer to Illus. 67—also see "Timing Ignition By Piston Position," Page 86.

Turn engine in direction which it runs until tappets indicate front cylinder is on compression stroke (directly after front intake valve closes). Continue turning engine slowly until flywheel timing mark is slightly forward of center of inspection hole in left crankcase.

First make sure mark (4) on circuit breaker head and hole in circuit breaker adjusting band line up before installing circuit breaker.

Install base gasket and circuit breaker head tension (ground) spring on circuit breaker base assembly and insert shaft and shaft gear all the way down into place in timing gear case cover trying to locate mark on small end of breaker cam in position shown in Illus. 67. Do not as yet install base mounting screws.

Install circuit breaker head on base with control lever (8) within advance and retard quadrant as shown. Do not install cover retainer until later. Fully advance lever (8) (turn counter-clockwise) and observe how closely mark (4) on breaker cam lines up with breaker lever fibre. If it does not line up, lift circuit breaker base and turn shaft gear so its engagement with its driving gear is changed one tooth. Check again according to breaker cam mark. Repeat this procedure until gear engagement is attained which closely aligns mark (4) and breaker lever fibre. When this has been accomplished, make sure base is turned so low tension wire is toward rear of engine and secure base with screws and lock washers.

Make sure low tension wire is allowed enough slack within circuit breaker head to be free for full advance and retard movement.

Install head on base and secure with ground spring and cover retainer. Be sure ground spring is in its proper place so when cover retainer ends are inserted through holes in circuit breaker head, they also register into spring locating notches. Otherwise, spring will have no tension and the head will be loose on its base. Contact points and condenser are grounded through circuit breaker basé and this spring holds the head in close contact with base, thus insuring a good ground.

Provided circuit breaker cam shaft gear has not been replaced and mark (4) on side of circuit breaker head and hole (4) in adjusting band are still in alignment, and breaker point gap is correctly adjusted, engine is now timed according to original factory setting. See "Recommended Recheck of Ignition Timing," Page 83.

Installing Circuit Breaker and Timing Ignition

(1947 Models)

Information under "Installing Circuit Breaker and Timing Ignition (O.H.V. Engine)," 1946 and Earlier Models, Page 81, and "Installing Circuit Breaker and Timing Ignition (Side Valve Engine)," 1946 and Earlier Models, applies to respective 1947 Models except as follows:

1. A timing adjusting stud (also serves as advance and retard lever) replaces the adjusting band and advance and retard lever used formerly.

2. Circuit breaker base assembly is installed with timing stud slot facing forward. The slot governs maximum advance and retard.

3. Provided outer edge of timing adjusting stud • plate is still in alignment with mark on side of t circuit breaker head, breaker point gap is cor

» rectly adjusted and circuit breaker assembly is ^f* installed as described for 1946 and earlier Models (except as mentioned above), engine is now timed according to original factory setting.

Recommended Recheck of Ignition Timing

(1946 and Earlier Models)

Even though all marks are in perfect alignment, same as engine was originally timed, timing may change somewhat after engine has been in service for a time, due to normal wear and seating of the various parts that affect timing.

If circuit breaker cam shaft gear was replaced, there is a possibility that timing may be off considerably with original factorv marks in alignment. Shaft gear pin hole is not drilled in any definite relation to gear teeth, and therefore, if a gear is installed in which the pin hole is drilled in a different location from that in original gear, circuit breaker head must be shifted as necessary (disregard original factory mark (4) on circuit breaker head) to correct ignition timing.

Since accurate ignition timing is the first essential to good engine performance, it is advisable, after ignition has been timed according to marks as explained above, to recheck as follows:

See that circuit breaker points are adjusted for correct gap of .022". Advance breaker lever (8) fully. Turn engine in direction in which it runs until front cylinder is on compression stroke and continue to turn it ahead slowly until narrow cam (the one with timing mark), just starts to open breaker points.

An accurate check as to when points just start to .¿i* open can be made with a test lamp as follows:

If engine is installed in chassis, connect one wire of test lamp to coil rear terminal along with low tension (circuit breaker) wire; connect other wire to ground and turn ignition switch "ON." As long as points are closed, lamp will remain out; as points start to open, lamp will light.

When exact position is found, where points just start to open, flywheel mark should be at rear edge of inspection hole for O.H.V. Engine—see Illus. 66, or slightly forward of center of inspection hole for Side Valve Engine—see Illus. 67. If mark is not in proper location, adjust timing as necessary by loosening screw (7) which loosens adjusting band, and shift circuit breaker head in band.

If flywheel timing mark is forward of rear edge of inspection hole—O.H.V. Engine, or more than slightly ahead of center in hole—Side Valve Engine, timing is late. To correct, shift circuit breaker head against rotation (counter-clockwise) of breaker cam.

If flywheel timing mark is to rear of inspection hole and not visible— O.H.V. Engine, or in center of hole—Side Valve Engine, timing is early. To correct, shift circuit breaker head with rotation (clockwise) of breaker catn.

With ignition timing correct, front piston is 7/16" —OM.V. Engine, or 11/32"—Side Valve Engine, before top center, on compression stroke, when points just start to open. Aj this point, spark occurs, igniting front cylinder fuel charge.,

Ignition timing should be checked in this manner every 2000 miles.

Recommended Recheck of Ignition Timing

(1947 Models)

Information under "Recommended Recheck of Ignition Timing," 1946 and Earlier Models, applies to respective 1947 Models except as follows:

If flywheel mark is not in proper location when points just start to open, readjust timing as necessary by loosening timing adjusting stud lock nut and shifting circuit breaker head as necessary.

Installing Pistons

It is assumed that piston-cylinder fitting, also pin and ring fitting have already been given due attention as per information under "Refinishing Cylinders Oversize and Fitting New Pistons," Page 45, "Emergency Piston and Ring Service," Page 87, and "Piston Rings," Page 89. Whether new or used pistons are being installed, the rings should be new. It is not practical to reassemble an engine with used rings, even though rings may not be very badly worn.

Install pistons according to instructions under "Piston and Pin," Page 88. Handle pistons carefully so they will not be burred, cracked or otherwise damaged.

Aligning Connecting Rods

In refitting and reassembling connecting rods, and finally fitting pistons, rods may possibly be bent or twisted, throwing upper bearing and lower bearing out of alignment with each other to some extent. Therefore, after pistons have been installed, rods must be checked and re-aligned as may be necessary. If a rod is left bent, or twisted, piston has a "cocked" relation to cylinder bore and the result is excessive noise and rapid wear.

Check rod alignment by means of piston squaring plate (Harley-Davidson special squaring plate. Part No. 11919-X), as shown in Illus. 70. Be sure crank-case face is clean and free from burrs so that squaring plate seats fully. Note: 74" O-H.V. piston skirt is cut away at bottom (below piston pin) for flywheel clearance, therefore, it cannot be used with squaring plate for checking rod alignment. Temporarily install and use a 61" O.H.V. or Side Valve Engine piston to check 74" O.H.V. rod alignment.

If a rod is in perfect alignment, piston bottom will rest squarely on plate *with flywheels turned so that crank pin is in either fdrward or rear position. Bear in mind that this check, to be accurate, depends upon checking with crank pin in both forward and rear positions, as it is the change of rod angle, resulting from changing crank pin from one position to the other, that influences the seating of piston on squaring plate and thus indicates whether or not rod is in alignment.

Rather than depend entirely upon visual check, as to when piston seats squarely upon plate, insert narrow strips of paper of equal thickness underneath piston, one on each side, below piston pin, as shown in Illus. 70. Press piston down lightly with finger tips resting on center of piston head and pull first one paper, then the other, partially from underneath piston. If piston is perfectly square (rod in alignment), both will have the same amount of drag.

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