Often asked: What Is Single Fire Ignition On Harley Davidson?

What’s the difference between single fire and dual fire ignition?

What are the benefits? Dual fire ignition systems fire both spark plugs from a single coil at the same time. Single fire ignitions separate the firing pulses, only firing the cylinder under compression. The main advantage of dual fire systems is simplicity and low cost.

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 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.

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What does a Harley ignition module do?

The module sends a signal to the ignition coil, which turns 12 volts into thousands of volts to make a hot spark. The ignition coil is connected to the spark plugs through spark plug wires, which are specially designed for their specific duty.

How do you test a single fire coil?

Set the ohmmeter to read resistance on the “Rx1000” setting. Measure the resistance across the two larger terminals on the coil. The ohmmeter should read between 10,000 and 12,500 ohms. If the meter reads outside of the ranges for either of the above measurements, then the coil is faulty and should be replaced.

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.

Why do planes have 2 magnetos?

REDUNDANCY Airplanes have two magnetos, left and right, each of which fires one spark plug per cylinder, creating a redundant system that allows the engine to operate at full power independent of the engine-driven alternator.

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.
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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.

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. Make sure the wires aren’t loose that connect to the coil.

How do you test a Harley Davidson ignition module?

How do you test a Harley ignition module?

  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.

Why does my bike have no spark?

If you are having a no-spark problem, a good place to start after ruling out shorts, grounds, switches and spark plugs, is the ignition coil, spark plug caps and wires. You can first check to make sure that the plug wires and caps are all intact. A breakdown in the insulation can cause arcing in the plug wire.

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