FAQ: Which One Is Better A Single Fire Or A Dual Fire Coil For A Harley Davidson?

What is the benefit of dual ignition?

Dual ignition is most commonly employed on aero engines, and is sometimes found on cars and motorcycles. Dual ignition provides two advantages: redundancy in the event of in-flight failure of one ignition system; and more efficient burning of the fuel-air mixture within the combustion chamber.

Is my Harley single fire or dual fire?

With the exception of the new Twin-Cam 88 and late model Sportster 1200 engines, all carbureted Harley-Davidson® engines have been dual fire. A single coil winding with two high voltage output terminals fires the spark plugs on both cylinders simultaneously. Each plug is fired twice during each four stroke cycle.

What is single fire ignition on Harley-Davidson?

The single fire ignition uses separate coil windings and electronics to fire each spark plug independently. Spark firing occurs only on the compression stroke. Conversion of older carbureted Harley-Davidson® engines to single fire is highly recommended.

How do you test a Harley-Davidson single fire coil?

How to Test a Harley Davidson Ignition Coil

  1. Turn off the motorcycle. Allow the engine to become cool to the touch before proceeding.
  2. Disconnect, by hand, the two spark plug wires from the coil.
  3. Set the ohmmeter to read resistance on the “Rx1” setting.
  4. Set the ohmmeter to read resistance on the “Rx1000” setting.
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What are the disadvantages of a dual magneto ignition?


  • It has a starting problem due to the low rotating speed at the starting of the engine.
  • It is more expensive when compared to a battery ignition system.
  • There is a possibility of misfire due to leakage because the variation of voltage in the wiring can occur.

Why do Hemis have two spark plugs?

“The use of a pair of spark plugs per cylinder effectively doubles the fire power (pun intended) of the ignition system, which is needed for a cleaner, more complete burn of the large air/fuel charge-particularly at higher RPM, as the valves open and close more rapidly.

Is single fire or dual fire ignition better?

The main advantage of dual fire systems is simplicity and low cost. The advantage of single fire systems are smoother engine operation and the elimination of the popping that sometimes occurs when long duration camshafts are used. There is no horsepower advantage with single fire ignition systems.

What’s the difference between a 3 Ohm coil and a 5 ohm coil?

The resistance of the coil determines how much current flows through the ignition system. The 3 ohm coils, because of their lower resistance, pass more current and therefore run warmer than the 5 ohm coils. Damage to the coil and ignition will result and will NOT be warranted.

What does a Screamin Eagle ignition module do?

This module is programmed to allow the engine to turn 7000 RPM and retards timing by 5 degrees at wide-open throttle.

How do I know if my Harley ignition module is bad?

Usually when the module goes bad the bike either won’t start, or starts fine when cold and starts cutting out or dies when it warms up, and won’t restart until cold.

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Does a ignition coil have to be grounded?

The simple answer is no, the coil case does not have to be grounded for the ignition to work properly.

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