Let’s talk about Tri-Spark

Grant Tiller

I am a huge fan of Tri-Spark, and have fitted a few of them with great results!

However, I think they are given a hard time in the groups and forums for their reliability.


It’s true – there was an issue a good few years ago with one of the components (I believe it was manufactured by Honeywell) that was not able to withstand the environment it was operating in.

Running everything inside the points cover means that high temperature and high vibration is more of an issue compared to the more common practice of running a simply pickup in the points cover, and having everything else in a separate control box.

However, this Honeywell part didn’t live up to the manufacturers own specs, so the failure was hardly the fault of Tri-Spark.

Stephen Kelly (the owner at Tri-Spark) worked with bike owners that experienced failures to make sure they were either reimbursed or given a replacement unit.

These problematic units look different to the ones you buy today – they have an anodised front cover, and no test button on the front. So they are easy to spot!

Grant Tiller


I think the other thing that needs to be considered, but is often overlooked is the wiring.

With everything packed into one unit, it is essential that the wiring to this is sound and reliable.

A lot of people will be reusing the BY (black/yellow) and BW (black/white) wires that used to go from the points up to the condensers, so it is essential to make sure the wires are in good condition and are not damaged or chafed in any way.

It’s a good idea to renew the rubber grommet that goes through the engine case – many people don’t know there should be one, as it is often missing. This will also help stop water ingress from the outside world into the points cavity.


The other point I think is worth consideration is the Positive connection.

The Tri-Spark is, as standard supplied with a ring connector on the red wire, which should be screwed under the 2BA standoff for the points cover.

I don’t think this is a good idea.

Think about the route back to the Positive terminal on your battery:

Assuming you have correctly secured your red wire to the engine side of the head steady, and not the frame side, there is still a complex and dirty route ahead for the power to travel:

  • bolts covered in Loctite and thread lubricant
  • paper gaskets (base gasket and timing cover gasket) covered in Wellseal
  • head gasket, which may not be conductive if it is a composite one
  • plates that are painted or powder coated

If you haven’t moved your red wire from the frame side of the headsteady to the engine side of the headsteady, you also have isolastics to get through as well! These are a great electrical insualtor as well as a vibration isolater!!!

Of course, if you are running a MK3 Commando, or a bike with an aftermarket electric starter kit, none of this should be an issue, because you should have a very heavy gauge cable running from the crankcase (right next to the starter) directly back to the battery positive terminal.

With all this in mind, I feel it is a great idea to run the red positive wire of the Tri-Spark directly up to the coils, instead of relying on getting it through the engine casing.

As an example, on our bikes I extend all three cables with soldered and heatshrinked joints that are wrapped in cloth tape – so all three wires run together up to the coils.

Grant Tiller

It’s quick and easy to do, and will rule a massive variable out from troubleshooting in the future.

After all, if you were running an electronic ignition unit with a seperate control box, it would probably live under the fuel tank, and tap into the red in exactly the same way.

I feel this is so important, that I have gone back through all the existing wiring diagrams I have posted on this site, and altered each drawing that contains a Tri-Spark electronic ignition to show the red wire going back to the coil.

Here is an example of what I mean:

Grant Tiller


The other point to think about is RFI (radio frequency interference) and EMI (electro-magnetic interference)

It was found that certain Podtronics regulator/rectifier units are known to cause issues with Tri-Spark ignitions.

Tri-Spark used to be a reseller of Podtronics regualtor/rectifiers and found that some of their units caused a misfire at between 3,000rpm and 4,000rpm.

You can read the Tri-Spark technical article about this topic by click here:

Grant Tiller

I personally find Podtronics to be very poor quality, so this is not a surprise to me at all.

Tri-Spark have recognised the issue and have made a choke/filter available for purchase that will address this problem for those that are experiencing a misfire/flatspot.

Grant Tiller

You should note that this is a Podtronics issue – their circuitry is producing a dirty/noisy supply.

The above filter/choke is connected to the reg/rec.

Grant Tiller

Hopefully someone, somewhere will find this article useful.

I have several Tri-Sparks, have them wired up properly and I have not seen any reliability issues.

I don’t think I am lucky – these are good systems.

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