Triumph Trident Boyer Problems

Updated July 20, 2017

From time to time the Boyer Electronic Ignition may fail in a car or motorcycle. You can take steps to solve the problem and get your Trident motorcycle operational again.

Boyer-Bransden electronic ignition systems are a popular upgrade for British cars and motorcycles. Replacing the original mechanical point style ignition with a modern electronic upgrade adds both power and reliability. On a Triumph Trident motorcycle, the Boyer ignition works by firing all three cylinders on the same switch signal from the stator. On every firing pulse, a properly operating Boyer system will give a hot blue spark at the plug on all three cylinders simultaneously. If the motorcycle displays a problem on only one cylinder, then the fault does not lie with the Boyer ignition. The problem then may lie with the spark plug, spark plug wire, ignition coil or internal cylinder fault.


Ensuring that the ignition box unit is getting proper power supply is fundamental to resolving any problems. Check the main power feed wire to the ignition box with a 12 volt, 21 watt test light. The test light should glow brightly and steadily on both the power feed wire and on the ground wire of the ignition box. Look for loose connections or bad grounds in the wiring harness if the bulb glows dimly or if the light is unsteady.


Locate and disconnect the wires from the ignition box going to the stator plate. Turn the ignition on and touch the two wires together briefly while observing the spark plugs. This simulates the stator, sending a pulse signal to the ignition box and "fooling" it into thinking the engine is running. If sparks are present at the plugs while touching the wires, then the ignition box is in proper working order. If no spark is observed, then the ignition box should be repaired or replaced.

Stator and Rotor

Check the stator plate for loose or broken wires, burn marks or loose magnets. If any of these symptoms are present, the stator is bad and should be replaced. Use a multimeter to check the resistance of the pickup windings. Replace the stator if the resistance is uneven between the windings or if the meter shows an open circuit. Check to see if the rotor is tight on the end of the crank shaft cone; tighten or replace it as required.


The Boyer ignition works best when the primary ignition coil resistance is less than 3 ohms. Stock coils may cause ignition malfunction if the total resistance is over 8 or 9 ohms. Double-check the wiring to ensure correct installation of the ignition box and stator. Trident motorcycles built before 1978 are positive ground. A Boyer installed in a negative ground configuration will not work correctly. Boyer ignitions must have between 8 to 16 volts to operate.

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About the Author

Michelle Schaefer began writing in 1998 for "The Pennsylvania Homeschooler" with advice for parents educating their handicapped children at home. She earned a bachelor's degree in education from Kutztown University in 1991.