Factory Timing Marks


MODEL XLCH front CYLINDER piston 11/16 IN. (45°) before TOP DEAD CENTER

1 Induction Coil

2 Rotor

3 Condenser

4 Circuit Breaker Points

5 Safety Gap Points (1964 & earlier)

6 Ignition Cut-out Terminal Post

7 Coil Secondary Terminal Spring

8 Cam Follower

9 Cam

10 Pivot Screw

11 Adjustment Screw

12 Adjustment Pry Location

MODEL XLCH front CYLINDER piston 11/16 IN. (45°) before TOP DEAD CENTER

13 Cam Oiler Felt

14 Magneto Mounting Bolts & Nuts (1964 & earlier) 14A Magneto Mounting Bolts (1965)

15 Magneto Advance Stop Screw (1965 to early 1967)

16 Timing Inspection Hole

17 Timing Mark

18 Narrow Cam Lobe

19 Coil Lead Wire

20 Breaker Point Terminal Post

21 Control Wire (1965)

22 Swivel Block (1965)

23 Control Wire Set Screw (1965)

Figure 5F-6. Magneto

When advancing spark, hold pressure on magneto housing so it follows movement of adjusting screw. However, do not change adjustment of screw more than one turn away from established factor setting since this will affect retarded timing. Correct amount of timing retard for starting engine will be provided by setting stop screw (15) so that distance between screw head and its seat on plate is approximately 3/16 inch.

The late 1967 XLCH model does not have an advance stop adjustment screw. A slot and pin in the base plates control the degree of retard to a fixed amount. To check the ignition timing proceed as follows:

1. Remove spark plugs to permit engine to turn easily; remove plug from timing inspection hole (16) in left side of crank case. Then remove front intake push rod cover so that opening and closing of valve can be observed. Remove magneto cover by removing four screws and set circuit breaker point gap at exactly .015 in. See "Adjusting Circuit Breaker Points."

2. Turn engine in direction in which it runs until just after front intake valve closes and piston is coming up on compression stroke. Continue turning engine very slowly (less than one-half revolution) until timing mark (170 on flywheel is aligned exactly in center of inspection hole (16).

3. On 1964 and earlier models see that timing marks on magneto base and magneto mounting plate are in alignment.

4. Narrow cam lobe (18) should now be located counterclockwise from cam follower (8), and breaker points should be just opening. If points have opened early or have not yet opened, the magneto must be shifted on base to get correct timing. On 1965 to early 1967 model, minor adjustment can be made by adjusting screw (15). (Be sure magneto is in fully advanced position.)

A timing light can be used to accurately determine when points open as follows: Disconnect coil lead wire (19) from breaker point terminal post (20) to open coil connection. (Other wires should remain attached to terminal post). Connect other terminal of battery to the magneto metal housing. When the points are closed, the lamp will be on and when the points open the lamp will go out.

5. If points cannot be opened by shifting magneto housing within limits of slots in magneto mounting base, or if point opening occurs after magneto housing has turned to a position where it will interfere with the carburetor air cleaner, it is probable that timing according to original factory marks has been lost. This would occur if magneto were loosened and lifted far enough so its drive gears become un-meshed, or if the case were opened and gears removed and installed, or if magneto circuit breaker parts were removed and replaced for any reason. In this case unbolt magneto from case and lift far enough to bring its driving gears out of mesh. Turn circuit breaker cam approximately as much as cam appeared to be out of required position, and push assembly back down into gearcase, re-engaging its drive gears. If circuit breaker still cannot be shifted far enough to obtain point opening, repeat operation of lifting magneto and changing engagement of driving gears until proper point timing is obtained.

After correct timing is obtained, secure magneto base mounting bolts and recheck ignition timing as follows: Turn engine in direction in which it runs until just after front, intake valve closes and piston is coming up on compression stroke. Continue turning engine very slowly until timing light goes out, then see if flywheel timing mark (17) is in center of hole. If timing mark is not in center of hole loosen mounting bolts or turn adjusting screw to shift magneto as required. When rechecking always turn engine in the direction it runs. When correct timing is obtained, retighten the magneto base mounting bolts, reconnect coil lead wire to point terminal post and reinstall magneto cover.

CHECKING TIMING WITH STROBE-LIGHT Where a strobe-light timing light is available, adjusting and checking ignition timing is done with engine running at a fast idle speed, viewing flywheel timing mark in crankcase timing hole. This method is recommended since it is made under actual running conditions.


Remove carburetor from the motorcycle to provide sufficient clearance for removal of magneto assembly. See Sportster Fuel System, Section 3F.

Disconnect spark plug cables at magneto. Disconnect ground switch terminal wire at magneto terminal (6). Remove tachometer drive assembly if used. Loosen control wire set screw. Remove the two mounting nuts and bolts (14 or 14A). Lift shaft and housing assembly from gearcase.


If magneto adapter plate (47 or 47A) has been removed make sure oil seal ring (49) and gasket (48) (if used) are in place before mounting adapter plate on gear case with screws (46). Install inside magneto mounting bolt (44), in place and assembly screws (46). On magnetos having manual retard, adapter plates (47A) and 47B) must be installed together.

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