73 Ironhead having a Strange Spark Issue..... Previous owner added electric start. I've changed plugs, wires, coil, battery, breaker, ignition switch. Now here's where it gets strange for me. With the ignition switch ON, no spark when I turn it over, BUT as soon as I turn the key to OFF, it gives me good spark for that brief click over to OFF. If a quickly turn key from ON to OFF plugs/Coil have strong spark. Why Im I not getting spark in the ON position. Need to get this thing fired up and Ride, HELP !!

 

Do you have a voltmeter you can use to measure the voltage coming out of the igntion switch with the switch on? If the only thing you're doing when you do get good spark is turning the switch off, it sounds like your replacement ignition switch isn't making contact inside until you're switching it off.

That's assuming the PO didn't wire something up wrong when he added the electric start.

As always with electrical gremlins, check the ground connections of everything and make sure they're tight and good.

 

+1

I would replace the ignition key switch. These are not expensive and are easy to replace, and you get two new keys with it.

BTW, do not put anything extra on the key tag with your ignition key. The extra weight hanging there blowing in the breeze will wreck the switch.

 

Yep, checked everything with a volt meter from the switch to the coil. Everything is getting proper power. New switch is hooked up properly and getting contact. Spoke to a very cool/knowledgable guy at the local HD Dealership and he said the quick spark I get when I turn OFF is just "residual" spark and means nothing. He said don't get caught up on the fact that it sparks when I go to OFF, but that I'm not getting Spark when ON. Pull the timiming cover to replace the points this morning and found a "Mallory" electronic performance E-Spark Ignition. Dealership guy says sounds like that could be my problem since everything else has been replaced. Ordered a New one, be in on Tuesday and should see if that does the trick.

 

before you spend the buck on a new breakerless ignition unit, check the wiring from the coil to the ign. unit. If the wiring is shorted to ground, it would also cause these symptoms.

 

Thanks Guys, The New "E-Spark" electronic ignition module has been installed and the bike runs Crazy Great! Appreciate all the advice.