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Fixed my clutch and got just enough blissful miles in to develop/notice an intake leak on the 1979 FXE. Fixed that with an FNA tite seal kit, replaced the fuel filter, and then hit the starter.
Cranked away, would only fire with full throttle, and was boggy at that. Eventually realized no spark to the front cylinder.
Running a Dyna S ignition pictured below with what appears to be the coil that comes with the kit. I have isolated the issue to the coil by doing the following one step at a time:
Tried a second set of spark plug wires and new spark plugs // Using the same plug wire and spark plug, did a spark test (grounded to the frame and in the dark) with each terminal on the coil // Switched the wires connected to the ignition coil posts.
Each time I could only get spark out of the top terminal (below the blue wire in picture). This was still the only terminal on the coil that provided spark when the blue, and white & red wires were reversed.
Seems like the bottom terminal on the coil is fried. However, I *think* this is a dual fire system (no idea really) and I have read that dual fire coils can't go bad in only one terminal. Anyhow, thought I'd come here before sinking another $100 into this thing.
Yes, that is a dual fire system. Technically there is no "botttom coil" , you would have 3 connections if seperate coils and thus single fire. Swap the plug wires at the coil and see if it follows the wire. If it does, bad coil. My 8-ball says bad ignition.
FYI any 5 ohm coil will work with that, can try a old stock one to test the system. And yeah that's the standard dual fire unit, single fire has two pickups.
Oh, I'll add this with the Dyna-S the sensor either works or don't, no in between as you describe.
Last edited by TwiZted Biker; Feb 9, 2023 at 11:55 PM.
Yes, that is a dual fire system. Technically there is no "botttom coil" , you would have 3 connections if seperate coils and thus single fire. Swap the plug wires at the coil and see if it follows the wire. If it does, bad coil. My 8-ball says bad ignition.
Testing the same plug and plug wire outside the bike on both terminals only gives me spark at the top terminal. Same deal if I swap the wires running from the ignition to the coil.
FYI any 5 ohm coil will work with that, can try a old stock one to test the system. And yeah that's the standard dual fire unit, single fire has two pickups.
Oh, I'll add this with the Dyna-S the sensor either works or don't, no in between as you describe.
I have an old 5 ohm drag specialties coil for an ironhead project with points that I hooked up last night to try and test the coil theory.
It was not happy with that. I pushed the started and the headlight went out, there was a click somewhere that Im assuming was a fuse or breaker etc, and some kind of unidentified 1 sec whine. Yikes.
I hooked the other coil back up and everything seemed more or less the same lights came on, starter motor cranked, and still only had spark at one terminal on the coil.
Google at least seems to think that other coil is points only
my experience if it's not a kick start you have to use a 3ohm coil it will only work with that but if you need a new ignition the ultima 2000I is your best buy it'll tell you if the coil not working it's preg ptogam from the factory
Points ignition use a 5 ohm coil to limit the current flowing through the points so they don't burn as our bikes don't have a ballast resistor in the primary circuit. Electronic H-D ignitions use a 3 ohm coil. My understanding is that Dyna S just replaces the points and uses the 5 coil.
Last edited by 84 Shovel; Feb 10, 2023 at 10:09 AM.
Points ignition use a 5 ohm coil to limit the current flowing through the points so they don't burn as our bikes don't have a ballast resistor in the primary circuit. Electronic H-D ignitions use a 3 ohm coil. My understanding is that Dyna S just replaces the points and uses the 5 coil.
As twizted points out above in the Dyna S manual, it shouldnt be a matter of Ohms. The Dyna S actually prefers the 5 Ohm and thats what they supply in the kit I believe.
However I have since read multiple posts scattered around where people say basically this: You can use an electronic ignition coil for points, but you cant use a points coil for electronic ignitions.
I havent found an explanation for why that is.
I will say the drag specialties 5ohm I tried swapping to did not work, to say the least. IDing the coil online led me to the lowbrow customs page offering it, where it is described as 5ohm for points ignition.
New 5 ohm coil coil comes in the mail today. Ill report back after throwing it in.
Last edited by adam3131; Feb 11, 2023 at 05:55 AM.
And just confirming the above, regardless of points vs electronic ignition, it shouldnt matter which posts on the ignition coil the wires are hooked up to correct?
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Ignition coil busted?
