What Coil Do I Need?
The many different ignitions available today can generally be used with a variety of different coil brands. Ignitions supplied on Twin Cam® and 2004-up Sportster® models are quite specialized and the factory coils supplied with them are also advanced and perform well in stock or performance applications.

Earlier (pre-TC) models with applications such as single or dual plug, and single or dual fire will affect which type of coil you may need to use. There are 3 basic types: O.E.M. Harley-Davidson® style coils which are shaped and mount like stock coils with two mounting holes and two wire outlets, typically used to upgrade dual-fire ignition systems. Next: There is the popular Dynatek post-mount coils which have a metal post that runs through the middle of the coil and has holes in each end for mounting; these coils require special mounting brackets to mount them properly. Last: Are the “two-in-one” coils for single-fire ignition systems that are actually two coils in one casing, made that way for easier mounting. These coils are generally slightly larger than stock, sometimes requiring special adaptors to retain the stock coil covers and can only be used on fully electronic (non-mechanical advance) ignitions.

You’ll notice that we list the ohms resistance for the coils we offer. It is important that the coil you select has the correct resistance as specified by your ignition system. Improper resistance can lead to module failure or malfunction. It is OK to use one manufacturers’ coil and another’s ignition module as long as the specs are compatible. How to decide which coil to use: see what type of coil is compatible with your ignition selection, then decide which mounting method would work best for you.

Here is a list of popular ignitions and their ohms resistance requirements:

  • Zipper’s Thunderbolt EV Ignition – 3.0 ohm
  • Original equipment points ignition – 5.0 ohm
  • ‘85-’99 Evolution® O.E. electronic – 3.0 ohm
  • Screamin’ Eagle® Evolution® modules – 3.0 ohm
  • Dyna ‘S’ ignition (street use) – 5.0 ohm
  • Dyna ‘S’ ignition (race use) – 3.0 ohm
  • Dyna 2000, 2000i – 3.0 ohm
  • Dyna 4000 (race only) – 0.7 ohm
  • Crane HI-4, HI-4E ignitions – 3.0 ohm
  • V-Thunder Controller & HyperFyre – 3.0 ohm
  • Spyke Ignition – 3.0 ohm
  • Compu-Fire ignitions – 3.0 ohm
  • RevTech Digital module – 3.0 ohm
Weight 1 lbs

Emissions Compliant

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