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General Category => General Discussion => Topic started by: baloo on September 21, 2025, 10:54:02 AM

Title: Any reason why I can't use Harley dual output coil?
Post by: baloo on September 21, 2025, 10:54:02 AM
1989 Mille GT 1000cc
So, replacing my coils and planning to replace point with  DynaIII eventually.
Looking for a SIGNIFICANTLY cheaper coil solution.

Is there any reason why I have to stick with 2 single 5ohm coils, and not use any 5ohm dual fire coil.  It's simpler to install, etc., and half the price of 2 Dyna singles.

See example of Dynatek Dual-Fire Ignition Coil 5 Ohm DC7-1 for Harley https://www.ebay.com/itm/203817999077?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20240305151706%26meid%3Dcd7c67d8456147feaaf53148758e1423%26pid%3D101729%26rk%3D4%26rkt%3D25%26sd%3D236072212907%26itm%3D203817999077%26pmt%3D0%26noa%3D1%26pg%3D3959035%26algv%3DDefaultOrganicWebWithV11WebTrimmedV3VisualRankerWithKnnV3AndUltBRecall%26brand%3DDynatek%26fpg%3D0&_trksid=p3959035.c101729.m1851


(https://i.ibb.co/cMRdWB6/image.png) (https://ibb.co/cMRdWB6)
Title: Re: Any reason why I can't use Harley dual output coil?
Post by: guzzisteve on September 21, 2025, 11:25:02 AM
Yes, if you use 2. One for ea cyl. Try it out & you'll see why.
Title: Re: Any reason why I can't use Harley dual output coil?
Post by: baloo on September 21, 2025, 11:44:33 AM
Quote from: guzzisteve on September 21, 2025, 11:25:02 AM
Yes, if you use 2. One for ea cyl. Try it out & you'll see why.
I don't understand:  Use 2 of the dual coils -- so one of the outlets on eaxh coil would not be used? Really don't want to buy a dual coil just to try it out.
How about this:  can I use ANY single coil (2 of them) that are 5ohm -- rather than the $$$ Dyna coils?
Title: Re: Any reason why I can't use Harley dual output coil?
Post by: Antietam Classic Cycle on September 21, 2025, 11:52:09 AM
Unless I'm mistaken, the Harley coils fires both cylinders at the same time - "waste spark". Not sure that'll work well on a Guzzi.
Title: Re: Any reason why I can't use Harley dual output coil?
Post by: Tom H on September 21, 2025, 12:25:56 PM
With respect....Some HD's are dual fire (spark at both cylinders at the same time) and some are single fire (1 spark per cylinder). My
'07 HD is single fire.

IIRR you can tell the difference by how many connectors it has.

Tom
Title: Re: Any reason why I can't use Harley dual output coil?
Post by: guzzisteve on September 21, 2025, 12:34:58 PM
Any 3ohm or 5ohm will work. They have cheap ones all over, folks used to go to Kmart years ago.
Title: Re: Any reason why I can't use Harley dual output coil?
Post by: baloo on September 21, 2025, 06:20:37 PM
Quote from: guzzisteve on September 21, 2025, 12:34:58 PM
Any 3ohm or 5ohm will work. They have cheap ones all over, folks used to go to Kmart years ago.
Thank you!  Somehow I got the illogical, but sustained, impression that only certain brand coils would work.  Illogical, but when the model is not familiar to me, there's always the possibility it is a unique feature of the brand....
Title: Re: Any reason why I can't use Harley dual output coil?
Post by: guzzista on September 21, 2025, 06:31:24 PM
Chyna Coils  ( Dyna copies) are about 80 bux or even less for the 3Ohm a pop  from 4 into one and are available on Amazon etc. I have not had any problems with them on Guzzis. IMHO they may very well be same as the D brand as I have not seem any Made in USA signage at least since the 3ohm green ones  I bought in the mid 1980's
No connection or affiliation with seller in link
https://www.amazon.com/Set-Magna-Single-Output-Coils/dp/B07K7VQVH2/ref=ast_sto_dp_puis
https://www.amazon.com/Set-Magna-High-Performance-Coils/dp/B01M069GK3/ref=ast_sto_dp_puis
Title: Re: Any reason why I can't use Harley dual output coil?
Post by: fotoguzzi on September 21, 2025, 09:34:10 PM
Should         Have                                                                                                                               Used                                                                    A                                                               Tiny                            U.                                                                       R.                                               L



                                                                                                                                                                                                                                                                               https://tinyurl.com/
Title: Re: Any reason why I can't use Harley dual output coil?
Post by: Antietam Classic Cycle on September 21, 2025, 09:47:26 PM
Quote from: fotoguzzi on September 21, 2025, 09:34:10 PM
Should         Have                                                                                                                               Used                                                                    A                                                               Tiny                            U.                                                                       R.                                               L



                                                                                                                                                                                                                                                                               https://tinyurl.com/

Or just clipped the link. This is all one needs from that big, long, link: https://www.ebay.com/itm/203817999077
Title: Re: Any reason why I can't use Harley dual output coil?
Post by: Kiwi_Roy on September 22, 2025, 08:03:54 AM
I'm running a Harley dual coil on my 76 Convert, seems to be ok.

Roy
Title: Re: Any reason why I can't use Harley dual output coil?
Post by: John Croucher on September 22, 2025, 08:26:38 AM
Duel tower-single fire coil.  Three wires.  Two ground from ignition points, one hot from kill switch.

The terms dual fire and single fire are confusing.