GSA Revcounter and 123 Ignition

[Avion100]

Can anyone confirm whether a GSA revcounter, modified for 2 cylinder engine will work with a 123 or other electronic ignition system.
I have the revcounter and intend to modify as described elsewhere on this site, but have a niggling concern regarding electronic ignition.
I would be grateful for any advice on this subject.

[moon monkey]

I have a tacho on my Lomax which has 123 ignition. It is connected to the coil, so I don't think the ignition technology would make a difference - they both drive the coil the same way.

[Rocketman1955]

I have exactly that set up - GS modified tacho & 123 ignition - without any problems.
Tacho must be connected correctly, otherwise the signal may be weak and the tacho needle will move erractically.

[Avion100]

Thank you for your replies.It's put my mind at rest. I'll get on with modifying my revcounter now.

[Avion100]

I thought I had all the answers, but alas, having procured a set of GS instruments and found out how to alter the revcounter to work on a 2cylinder engine, it seems that the revcounter I have is a 3 terminal variety but does not have a variable resistor.
Has anyone else come across this situation and found a solution?
I would like to ask Ivor Spark, the writer of the articles on modifying revcounters for help, but I have no idea how to contact him.
If anyone can offer any advice, or how to contact Ivor Spark, I would be very grateful.

[moon monkey]

You should have 12V, Ground and Signal (plus the light bulb). Is that what you mean by three connections?

[Avion100]

Yes I have the later revcounter with 3 terminals, 12v, signal and negative. My problem is that the instructions for modifying the revcounter to operate correctly on a 2 cylinder motor instead of a 4 cylinder motor, as detailed by Ivor Spark, require modifications to a resistor and a capacitor which I can do, but the revcounter has then to be adjusted by turning the adjuster in a variable resistor accessible via a hole in the rear of the case. My revcounter does not have a variable resistor. It is not that it has been removed, but that this must be a different version of the revcounter with perhaps revised circuitry.
I am concerned that if the circuitry has been revised, the suggested modification may not work.

Unfortunately I am a mechanical engineer and don't have sufficient electronic knowledge to understand the circuit. It would be really useful if the person known as Ivor Spark is still around and could be contacted.

[Vyv Cox]

Unfortunately it seems there are several versions of three pin tachometers, not at all like the one described by Ivor Spark. I have bought three from auction sites, modified them according to the instructions without success.

I have subsequently bought a Chinese 2 inch tacho that does not match the speedo but does match all the other instruments. Needed a new dashboard but I was doing that anyway.

On another Lomax I have used an adaptor that only utilises the coil and dial of the tacho, all electronics being external. I have posted on this elsewhere on the forum.

[Vyv Cox]

The company who provided the kit and instructions are called Spiyda. Worth talking to them, they are very helpful.