imported post
Rod wrote:
I'm looking for help on a 1981 Interstate that has melted both spark units. I have found two to replace them but I'm looking for help on WHAT would make this happen? The guy that had the bike before me put on a bunch of lights and switches that have turned into a spagetti farm could that be part of the problem? anyhow thanks for any help...Rod :cooldj:
Rod, it's really just a guessing game over the Internet.
Things that will fry an E.I spark unit are:
Too high of a voltage to the unit while running (check your charging voltage while in operation)
A unit that stays powered with the engine turned off & a closed trigger transistor (make sure the uint(s) power down with the ign switch turned off)
High resistance in a spark plug, or plug wires, or resistor caps (probably would only happen on one unit not two but worth a look)
Excess heat in the area those units are operating in (look for proper heat baffling & missing heat shields)
Some sort of a high voltage spike traveling back down the unit's power wires or trigger wires (make sure ANY added light or accessory control relays have clipping resistors or clipping diodes added across theinternal coilsto remove any high voltage reverse spikes when the relay is shut down)
Just plain old units to begin with maybe cracks in the cases or any other way moisture could get into the units.
Possibly someone jumped the bike from a high voltage supply or hooked jumper cables up backwards at one time with the ign switch left on (just a guess here)
You really should cut out all that crappy wiring & start fresh & make a new neat wire harness with everything neatly accounted for & powered correctly.
Twisty