1. Disconnect the Black/Yellow stop wire AT THE POWER PACK and retest. If the engines' ignition now has spark,
the stop circuit has a fault. Check the key switch, harness and shift switch.
2. Disconnect the Yellow wires from the rectifier and retest. If the engine has spark, replace the rectifier.
3. Check the cranking RPM. A cranking speed of less than 250-RPM will not allow the system to spark properly.
This can be caused by a weak battery, dragging starter, bad battery cables or a mechanical problem inside the
engine.
4. Inspect and clean all engine and ignition ground connections.
5. Check the stator and timer base resistance and DVA output as given below:
WIRE READ TO OEM Ohms CDI Ohms DVA (Connected) DVA (Disconnected)
Brown Brown/Yellow 835-985 (1973) 650-850 150-400 V 150-400 V (*)
Brown Brown/Yellow 555-705 (1974-77) 650-850 150-400 V 150-400 V (*)
Black/White (#1)White/Black (#3) 10-20 35-55 0.6 V + 0.6 V + (#)
Black/White (#2) White/Black (#4) 10-20 35-55 0.6 V + 0.6 V + (#)
Black/White (all) Engine GND Open Open 150-400 V (a) N/A
White/Black (all) Engine GND Open Open 150-400 V (a) N/A
(*) This reading can be used to determine if a stator or pack has a problem. For instance, if you have no spark
on any cylinder and the stator’s DVA reading is low – disconnect the stator wires and recheck the DVA output. If
the reading stays low – the stator is bad. If the reading is now within spec – the pack is bad.
(#) This reading can be used to determine if a pack has a problem in the triggering circuit. For instance, if you
have no spark on one cylinder and the timer base’s DVA reading for that cylinder is low – disconnect the timer
base wires and recheck the DVA output. If the reading stays low – the timer base is bad. If the reading is now
within spec – the pack is bad.
(a) The trigger signal rides on top of the high voltage on these timer bases. Check stator DVA first. Then if timer
base DVA is 0.6 - 2.5 V, the pack is faulty.
6. If the timer base output is low, you may try to reset the air gap between the timer base sensor and the triggering
magnet using a Sensor Gap Gauge (553-9702) or use the following procedure:
a) Loosen the two mounting screws on the sensors and the nuts located in the epoxy on the outside of the heat shield of the
timer base.
b) Slide the sensors in toward the crankshaft until the sensor touches the stop boss located at the base of the sensor
mounting area. Tighten the mounting screws.
c) Coat the face of the sensors with machinists bluing or equivalent.
d) Install the flywheel without the key and rotate the flywheel at least one full turn.
e) Remove the flywheel and check to see if the trigging magnet struck the face of the sensors. If it did, back the sensor out
approximately 0.005” and repeat steps c, d and e.
f) If the ignition sparked, finger tight the nuts on the outside of the heat shield and coat them with RTV.
g) If still no spark, replace the sensor.
7. Check the DVA voltage on each Black/White wire to engine ground. You should have a reading of at least 150V
or more (while connected to the pack). If the reading is low, disconnect the timer base wires from the pack and
recheck the Black/White terminals ON THE PACK. If the voltage jumps up to an acceptable reading, the timer
base may have a problem in the internal wiring (possibly a thin spot in the insulation on one wire).
8. Check the center hub triggering magnet in the flywheel. A loose magnet can cause this problem.
9. Check the triggering and charge coil flywheel magnets for cracked, broken and loose magnets.
Hope this helps?
