Tri-Spark Classic twin

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May 16, 2008
Hello there,

A couple of people from this forum have contacted me and asked if I would join in and answer some questions about the new Tri-Spark ignition which I am very happy to do.

I know from having done some work on Nortons that finding a spot for a black box is not so easy. The Tri-Spark ignition kit has all the electronics built into the stator or pick up unit which makes the whole installation process very easy.

One question that came through my email this week was "should I fit a 3 phase alternator with your ignition - I hear electronic ignition is power hungry"

The Classic twin Ignition and the others we make have a feature that minimises power usage while still producing the full output from the coils.
We do this by turning on the coils just before the spark so as not to waste power. This saves lots of battery especially at low RPM. You will have effectively 2 extra amps in the system that you didn't have before. I use the stock Alternator on my Trident and my Tiger 750 and both always start easy. I even use smaller batteries in them - only 4 amp hours.

You could change your alternator if you wanted but you probably don't need to.

I would recommend the use of 6 volts coils with the system. the stock Lucas ones or similar are a good choice and keep the stock looks on the Norton. We can supply these as an option.

The Norton System is different in it's rotation from the Triumph ones so it's important to mention the Model when placing an order.

The Tri-Spark unit has a feature which reduces kickback when starting the engine which is a plus with these larger twins.

Because the system is digital the features are consistent from one unit to the next plus there is the added benefit of a static timing light for easy accurate setup.

OK over to you,


Thanks for your quick response Steve.

My only reservations about the self-contained points housing units is that the life of the electronic components could be shortened by engine heat and vibration?

Do you expect these units will be reliable over a long period, Steve?

Member dgwilson remarked in the original thread about the Classic Twin ignition that you thought his '73 model would have 12V coils fitted as standard:

dgwilson said:
Steve kelly is saying the new Classic Twin unit needs 6volt coils to operate and He seems to think My 73 Norton has 12volt coils.

Normally the 1971-on Commandos would be fitted with two 6V coils and ballast resistor, Steve?

I hear your concerns about heat.

In an effort to minimise the chance of a problem, we have sourced all the best temperature rated parts available and potted the whole lot in epoxy under the black cap. The rating of all the parts is well above the temperature that the timing case reaches in our testing.

I have personally road tested a number of these systems in the tiger 750 since January and have found no cause for concern thus far.


Thank you.

Presumably for us in the UK we will be able to buy these units a little closer to home, at L P Williams?
Steve ,thanks for joining us. Always interested in the pieces you make.
Commando's are brutal on EI's where the wires enter the backing plate. Many people have found that the fix for this is to create a fusible link to the vibration, using short pieces of hollow braided wire at this junction.
Have you considered this problem in your design? Are the BSA and Norton systems the same units because of their like cam rotations or is the Norton a special because of the vibration needs? Would you mind publishing the link to some "on line" installation instructions for the new unit?
Steve, I will echo - thanks for participating on this board. I will add more question here:

You said, "Because the system is digital the features are consistent from one unit to the next plus there is the added benefit of a static timing light for easy accurate setup."

Is this static timing the only timing done on the entire set up?
Yellow_Cad said:
the added benefit of a static timing light for easy accurate setup."

Is this static timing the only timing done on the entire set up?

If the Classic Twin light is intended to be used the same way as the light on the previous Tri-Sparks, (I've got two of them) then the light gives an indication that the timing is reasonably accurately set, but a strobe still has to be used to do the final checking.

If the Classic Twin static light serves a different purpose, then hopefully, Steve can say how it differs to the previous Tri-Sparks?

Setting the Timing with the LED is done at the end of the installation with the ignition switched on. So long as the engine is rotated to the fully advanced crank postion, the timing will be set accuarately as the unit is rotated until the LED comes on.

Always a good idea to check with a strobe. I've done this a number of times and in my experience the timing will be very close to the mark done this way.

I would suggest that after setting and checking the timing a number of times you would be confident of this method.

With regards to the vibration and wires falling off...well I was warned of this some time ago by a reputable dealer. Have a look at the wire attachement we use on the classic twin and let me know what you think.

Tri Spark

Hi Steve - I have Tri-Spark fitted to both my BSA Rocket 3 and Commando - both brilliant !! - one question - the unit fitted to my Commando is the 'old' (18 months) system with the separate black box - does this incorporate the 'anti-kickback' feature you mention or is it only on the new 'all-in-one' system ?


The new Classic twin has a different sensor arrangement and software so it's very different from our original twin system. It can sense crank angle speed of crank and direction of crank as the rider is jumping on the pedal and it decides based on all that whether or not to fire the plugs.

I spent a long time on this feature, went through a few rounds of changes and bruised my ankle in the process (kicking the Triumph over) but in the end it was worth it.

Steve - that feature sounds like just the ticket for 1975 e-start Mark III 850 owners...

Hi Steve - I've just ordered one of your new systems for my Commando - I'll let you know how I get on. One question - the Tri-Spark,Boyer and Pazon systems all use magnetic pickups to signal the system, a few systems - Lumenition etc. use light-beams e.g. LEDs to signal. What are the benefits of one over the other ?

Thanks for the order. With the light beam systems, I understand some do not function with the points cover removed due to the ambient light getting in but maybe the new generation have overcome this problem?

Also if you have an oil leak , the oil will eventually coat the optics and they could stop working. As I understand things , magnetic is used almost universally in modern automotive applications.


mwoo, please let us know how you find the Tri-spark on your Commando, as I am also very interested in buying one, for two reasons.

1. The reduced likelyhood of kickback (although my MK3 doesn't kick back at the moment, possibly due to having an excellent battery.)

2. The reduced usage of power, when compared to the Boyer. I presume that I am correct in assuming this?
Tri Spark

Hi Reggie - yes I'll let you know how I get on - I'll fit the new unit when I:-

a) Give it a 500 mile service after the full rebuild (920 motor etc.)
b) Re-torque the head
c) Alter the needle on the single 36mm Amal Mk2 fitted (it starts and generally runs well but I think it's a be weak at third throttle and above).

The existing Tri-Spark is great but even so the 920 motor needs one hell of a kick to start it (and I'm 15 stone!) and if you're timid or get it 'wrong' it will kick back like a good-un (and hurt !!) thus my main interest is in the anti-kickback feature.


Mark Woodward
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