Tri-Spark Ignition Coils – Troubleshooting Guide

This guide provides comprehensive instructions on how to:

• Verify ignition coil compatibility with your system.

• Conduct resistance tests on ignition coils.

• Perform live testing using a spark gap tester.

Applies to the Following Coils:

• Tri-Spark Ignition Coil (Lucas Style) 6 or 12 Volt – Part No. IGC-1006, IGC-1012

• Tri-Spark Dual Lead Coil – 6 Volt or 12 Volt – Part No. IGC-2006, IGC-2012

 Common Symptoms of Coil Issues

• Engine misfires or runs rough
  

• No spark at spark plug(s)
  

• Hard starting or non-starting condition
  

• Coil gets excessively hot
  

• Intermittent spark loss after warm-up
  

• Backfiring or poor performance under load

Application & Compatibility Checks

• 6V Lucas style coils are typically used with an electronic ignition system (e.g., Tri-Spark Classic Twin) and are wired in series. 

• 12V Lucas style coils are typically used with a single cylinder bike fitted with an electronic ignition (e.g., Tri-Spark Classic Twin) or on a twin cylinder bike using points.

• 12V Coils should not be used with electronic ignition (e.g., Tri-Spark Classic Twin) in a twin cylinder application as they produce a weak spark

• Dual lead coils are designed for wasted spark systems (e.g., Tri-Spark Classic Twin).

• Dual lead coils are not suitable for British twin motorbikes using points.

• Warning: avoid using coils with a lower resistance than the system is designed for as this will cause overheating.

Tri-Spark Ignition Systems Compatible Coils

Classic Twin Ignition:

• Use 2 x 6-volt Lucas style cylinder coils -  (IGC1006) or

• 12-volt Dual Lead coil - 1 required (IGC-2012)

• For Single cylinder engine

• Use a 12-volt Lucas style cylinder coil  (IGC-1012)

For Magneto Replacements using the Classic Twin ignition, a 12-volt dual lead coil is included in the kit.

Classic Triple Ignition:

• Use 3 x 12-volt Lucas style cylinder coils - (IGC-1012) or

• 6-volt Lucas style cylinder coils 3 required (IGC-1006) plus Ballast Resistor (60-4516)

Triple Flex Ignition:

• Use 3 x 12-volt Lucas style cylinder coils - (IGC-1012) or

• 6-volt Lucas style cylinder coils 3 required (IGC-1006) or

• Single output 12V digital mini coil - 1 required: (IGC-4001) and Dual output 12V digital mini coil - 1 required: (IGC-4002)

Compass Ignition for BMW:

• 12-volt Dual Lead Coil (IGC-2012) or

• Dual Output High Performance Coil (Dyna Style) (IGC-3030)

• For twin plug heads: 6-Volt Dual Lead Coils (IGC-2006) - 2 required or Dual Output High Performance Coil (Dyna Style) 1.5 OHM (IGC-3015)

Compass Ignition for Yamaha XS650 and Moto Guzzi a 12-Volt Dual Lead coil is included in the kit. 

Step-by-Step Troubleshooting

1. Visual Inspection

• Check for damage to the coil body, terminal posts, or insulation.
  

• Look for cracks, oil leaks (oil-filled coils), or burn marks.
  

• Ensure the coil is firmly mounted and properly earthed.

 2. Primary Resistance Test

Use a multimeter set to Ohms (Ω). 

If reading is open circuit or zero (short), replace the coil.

Due to the low Ohms measurement of primary resistance, basic test equipment may not provide exact figures. Moreover, resistance measurements alone are not conclusive, as an internal coil fault can exist even if resistance measurements appear normal.

3. Secondary Resistance Test

Measure between the high-tension (HT) lead terminal(s) and one of the low-tension terminals.

Note: Resistance can vary widely between coils.  Open circuit reading suggests a faulty coil.

 4. Spark Gap Test

• Connect a spark gap tester to the high tension lead, replacing the spark plug.

• Set the gap to 8-10mm and operate the ignition. Observe if a spark jumps the gap.

• If the spark cannot jump the gap, reduce the gap distance.

• An ignition coil that produces a spark gap of less than 8mm should be considered too weak for efficient starting and running of the motorcycle.

5. Check Voltage Supply

• With ignition ON, use a multimeter to check voltage at the coil’s + terminal.
  

• You should see:
  

• Around 6V on 6V systems
  

• Around 12V on 12V systems
  

• Low or no voltage may indicate wiring or switch problems, not the coil.
  
  

6. Heat Check

• If the coil becomes too hot to touch after a few minutes of running (burning hot), it may be:
  

• Incorrect primary resistance (wrong coil for system)
  

• Excess dwell time or faulty ignition module
  

• Internal short in the coil

Installation Tips

• We suggest using resistor spark plugs or plug caps (5kΩ) if you suspect electrical interference is causing problems with the bike.
  

• Ensure good grounding / earthing at the frame and engine as required.
  

• Avoid mounting coils near extreme heat or vibration where possible.

If Problems Persist

If after testing the coil appears functional but spark is still absent or weak:

• Check the ignition module operation
  

• Verify wiring and connections
  

• Test using a known-good coil to isolate the fault

Need Help?

For further support, please contact Tri-Spark Technical Support with:

• Coil part number
  

• Bike model and year
  

• Ignition type used (e.g., Classic Twin, Classic Triple, Compass)
  

• Voltage readings and resistance test results