ET system – the solution

Tim Britton (December 2020, rebuild feature) wants to hear from anyone with a good experience of energy transfer ignition. He could be waiting some time.

The system is fundamentally flawed as it is trying to mimic the old flywheel magneto on two strokes. This uses alternating current with a wider wave formand fixed timing. With alternators the wave is much narrower and the timing is advancing and retarding so it cannot be optimised on peak current.

Tim implies that incompetent users are the problem but I think, in a 1960s ISDT, there were a number of ignition failures on ‘works’ bikes in the British team using this system.

PAL speedway magnetos are very good and use a remote coil with a low tension magneto that has wide ac waveforms. I have rigged up a similar system using a Lucas SR1 magneto (rewound) and a remote Femsa (Bultaco) HT coil. I have a test spark plug with the earth electrode removed and the spark jumps from the centre electrode to the body.

In the 1960s with a Trials

Cub I gave up on the ET system (phone home?) and put a Villiers 32A two-stroke engine in it. Tony Colman, via email.

The ET system was fundamentally flawed – Tony Colman’s response was to put a Villiers engine in his Cub. Looks lively enough!