Another Tri-spark Failure

1. Differing coils may make a difference to resistance (impedance) therefore current draw resulting in differing heat generation.
2 Some ignitions have different duty cycle for the coil drive V.S. RPM resulting in differing heat generation. Driving style could enter into the equasion...
3. How close the exhaust pipes come to the timing cover could affect the baking effect.

maylar said:

but then we expose the cam end and EI rotor to the elements.

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I don't think so on a TS...At least not the early version sitting right here within reach.

I spent 15 years doing engineering support for electronics testing which sometimes involved sometimes dozens of tiny thermocouples to characterize the thermal properties of new equipment. Failures got highly scrutinized . We would run them until they broke or pass the shake and bake.

Fast Eddie said:

ign coils (mourned directly onto spark plugs and buried inside the head)

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One plug/one cylinder so small duty cycle= lower heat generation.

All this guessing...with nothing (measurements) to back it up.
This really is TS Steve's(?) job as product engineer to measure the product and environment.

Fast Eddie said:

Lots of delicate electronics get mounted in some very hot environments on modern vehicles without failing

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IF LUCKY
$48K new RAM 3500 diesel 9200 miles, ABS brake controller /pump/ solenoid pack craps out!!! And I don't really go around constantly locking up the brakes...14 days to get a replacement in. My new silver truck some of you guys saw at the rally in Michigan.

Fast Eddie said:

Notwithstanding any of the above, I’m personally not yet convinced heat in the cover is the issue. Lots of delicate electronics get mounted in some very hot environments on modern vehicles without failing, inc ‘black boxes’ ign coils (mounted directly onto spark plugs and buried inside the head), direct injection injectors mounted in the heads, numerous sensors, etc..

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There is a big difference between coils and sensors that are mounted to a water cooled engine and a electronic ignition with a heat generating switching fet along with supporting components mounted to an air cooled engine.

A water cooled motor only swings from ambient to ~ 200 degrees F and stays there until it is shut down.

An air cooled motor sees much larger swings and the swings go along with the load and the amount of cooling air at the moment. A spirited ride on a Norton can easily bring the timing case cover over the 300 degree F. mark.

The failure is usually caused more by the temperature changes than the maximum temperature - just due to thermal expansion of the components, the circuit boards and soldier joints.

Personally I would want my ignition unit insulated from the varying temp of the engine case and with some venting of the cover -if I had to run a shake and bake ignition.

NOT SO. i have seen more than one older automotive ign failure that would run for a set time/distance and stop and after a cool down period start again. the early ford ei was common to do this exact thing and i also have had a chrysler do this and as soon as it stoped i hit it with freon and it ran again till it heat soaked again.

Madnorton said:

Over 16K miles on the improved version and no issues. If your tri spark stops, then later works it is highly unlikely the tri spark unit. Usually electronics fail and stay failed, they don't suddenly fix themselves.

The fact you took a hot air gun to it and it remained running says the unit was not at fault, and thanks for doing the test.

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bill said:

NOT SO. i have seen more than one older automotive ign failure that would run for a set time/distance and stop and after a cool down period start again. the early ford ei was common to do this exact thing and i also have had a chrysler do this and as soon as it stoped i hit it with freon and it ran again till it heat soaked again.

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Yes, the normal failure mode of the Tri-spark is to quit running when hot but run again after it has cooled.
That is why they make freeze mist for electronic diagnostics. Very often a little mist will bring a dead electronic component to life -temporarily.
The contraction from the cooling may bring open electronic circuits back into contact -either on the circuit board or inside the component itself.

Personally, I have been through four of them. I'm inclined to think it is the pick up magnets. I'm told that magnets lose their efficiency when hot. My current one has been trouble free for some time. On trips I now carry a spare, which, while expensive is easily changed over in about 15 minutes.

the freon trick was back when when we thought nothing about venting a little bit and you could buy r12 at a reasonable price

comnoz said:

That is why they make freeze mist for electronic diagnostics.

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I just love my Joe Hunt Maggie, first kick every time, runs nice and cool out in the breeze, no need for a battery, min wiring, plugs last forever, point's, coil and condenser all under one cover, steady idle and the faster it spins the bigger the bang (spark) can sit for months and will still fires up on one kick, runs great from slow revs to full revs, simple to maintain, haven't touched it in 8 years of use with 40k miles on it in that time, but I am not going to brag about it, much.

Ashley

lcrken said:

I don't think it's a bad ground or kill switch problem. When it wouldn't start, my friend checked several things (I wasn't there at the time), including power to the unit. It had power to the unit, and the green test light on the unit was lit. He also checked the coil with an ohm-meter, and it was good. But there was no spark. Because it is working again, I don't think there is much else to test, unless I was willing to do test rides until it happened again, and then try to do some quick troubleshooting while it was still hot. I'm just not interested in doing that. Better to use something that has a little better reputation for reliability.

I was initially drawn to the Tri-spark because of it's simplicity and it's idle stabilization design. From my previous life as an electronics engineer I knew that it was possible to design solid state circuits to tolerate very high temperatures with reliability, so I didn't worry much about the fact that the electronics were in the crankcase cover. Now I'm not quite so confident that the Tri-spark is up to the higher temperatures it sees. It is considerably more expensive to use mil-spec components that operate at elevated temperatures, and it may not have been possible to do so at a price Norton owners would be willing to pay. To be fair, we did get 4+ years of good use out of it.

Ken

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Did you run the self test while it wouldn't start?

bill said:

the freon trick was back when when we thought nothing about venting a little bit and you could buy r12 at a reasonable price

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Freeze mist is still readily available. I always keep a can on hand.

https://www.parts-express.com/max-p...MI0becrJax5QIVix6tBh0n8gi9EAQYASABEgKRHPD_BwE

Anything aerosol makes cold

marshg246 said:

Did you run the self test while it wouldn't start?

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No. I wasn't there when it happened, and my friend, who is quite a knowledgeable motorcyclist, but not a Norton guy, didn't know anything about the self test feature. He did determine that it had power to the unit, but no spark. After I picked it up and brought it home, I did the self test and it worked fine. So I tried starting it, and it started and ran fine. But by then it had been cooling off for over an hour.

Ken

For reference Ken, what coil system are you using?

MichaelB said:

For reference Ken, what coil system are you using?

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I’m wondering if this can be a significant contributory factor too...

Out of the 5 failure free units I’ve fitted, one (on the Commando) runs the cNw supplied coil. The three I’ve fitted to Triumphs use Tri Spark coils. One unit I fitted to BSA triple used Dyna coils (I forget which ones but I did look into correct compatibility at the time).

I read dd’s comments about different coils creating different heat, does this only mean different heat within the coil? Or can different coils create different heat within the EI unit?

Just wondering if the unit will be sent back to the maker for investigation...

comnoz said:

There is a big difference between coils and sensors that are mounted to a water cooled engine and a electronic ignition with a heat generating switching fet along with supporting components mounted to an air cooled engine.

A water cooled motor only swings from ambient to ~ 200 degrees F and stays there until it is shut down.

An air cooled motor sees much larger swings and the swings go along with the load and the amount of cooling air at the moment. A spirited ride on a Norton can easily bring the timing case cover over the 300 degree F. mark.

The failure is usually caused more by the temperature changes than the maximum temperature - just due to thermal expansion of the components, the circuit boards and soldier joints.

Personally I would want my ignition unit insulated from the varying temp of the engine case and with some venting of the cover -if I had to run a shake and bake ignition.

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Interesting Jim. ‘Mechanical’ failure of internal comments due to thermal expansion isn’t something I’d thought of to be honest.

Just for ref, and without getting into specific temps etc, my coil reference is an example I hold up just to try and demonstrate how electronic components have changed over the years, coils used to be oil filled and have to hang in the breeze, and they’d still fail! Nowadays they’re tiny, and buried deep in the hottest part of the engine.

Anyway, back to the heat topic: what kind of electrical related things can influence the heat inside the EI unit? Can different coils create more or less heat? Differences in wiring, or wiring issues, switches, etc? HT leads, plug caps, plugs used?

My bike doesn’t get used for the long rides through the desert that yours does Jim, but at 920cc and 11:1cr the engine clearly isn’t gonna run cool. From sitting in the paddock to completing a full track session is clearly going to create a huge temp differential. And even here in the U.K. this can happen in some pretty high ambient temperatures. And I can assure y’all that it often shows all the clear signs of being bloody hot!

So, what I’m wondering is why do some units fail and some don’t. Moreover, why do some people suffer multiple failures and others zero?

Surely something is causing different internal conditions ??

Like FastEd, I'm interested in why some units seem to repeatedly fail in the same bike. It seems a stretch to believe that there is so much variation between the units as they come out of the "factory," to account for this. And, even if so, why do the same folks keep getting the "bad ones?"

My '08 Trispark has been under the unvented points cover for over 10 years now with no issue. My bike operates under a variety of conditions, like everyone else - idling for extended periods in heavy town traffic, cruising along at 70-80MPH on the road, bursts through the ton, etc. So the temps vary however much they vary, again with no issue at all from the TS.

If it was just engine-heat related - wouldn't all TS's react the same way to being installed under the points cover and fail? OR, are some bikes getting much hotter than the "norm" for whatever reason? OR, is there some combination of components that don't work/play well together?

FWIW, my '08 TS has always used the twin stock-type coils though they are replacements of a German brand (as I recall) that I installed in '06. I ran OEM points/AAU from shortly after buying the bike in '06 until I installed the TS in '08.

MexicoMike said:

is there some combination of components that don't work/play well together?

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Yes the coil variations can have a different effect on the EI unit. When the uneducated make a decision on the resistance (DC) of a coil they might think they are testing something correctly. Yet coils are an inductive (AC) device. Two exact same coils(resistance) can have a few lamination of ferrite material and yet respond quite different if wrapped around a heavy load of ferrite laminations. The DC test may show the same results but in fact are NOT the same...there is much more science here than what you find in the kiddy sand box. Even with 40 years in the field and 6 years college physics/electronics I still sometimes feel like I'm over my head. I felt privileged working and learning for 15 years with PHD's in physics/electromagnetics and many EE's, but I'm still no expert...
Before I retired...
I would do performance tests on radar pulse transformers (king size coils) for 17-36KV typical and if they fail the spec, with a single coil and a case of cores, I would swap out the laminations until the HV coil would pass the rise time spec. All the cores from the same manufacturer...same batch #
How do you think we are getting incredible precision on our $30 coils when it was not possible with $10,000 coils?

How many know that as a transformer gets hot the copper winding resistance goes down, therefore the current goes up through the EI drive stage. sorry incorrect cause for current increase copper is POS cooef
Transformer and output transistor is cold on startup 12.8V and when running the battery voltage slowly charges to 14.3 or more. More current more heat...
Turn engine off and all cools down and resets?

Interesting stuff, DD. Thanks!

Makes my consider the fact that ignition points/AAUs don't have any issues with different coils!

Tri-Spark makes it clear that the static resistance of the coils must be in certain ranges.

I had one guy with a Triumph Trident with two old and one new versions Tri-Spark "heat" failures always with the right cylinder failing. On a triple you use 12-volt coils and they are fired individually. When the new version one failed, I made him a deal. Send me the unit and his three coils and I sent him replacements - if I found nothing wrong with his coils he didn't have to pay for the new parts. Guess what - he had two perfectly good 12-volts coils and one 6-volt coil! Current = Voltage over Resistance. He was drawing twice as much current through that coil - and therefore through that Tri-Spark circuit.

A twin has only one circuit in the Tri-Spark unit. The two coils in series place the same load on that circuit as each of the three circuits in a Triple. A subtle thing to consider is the plus and minus on each coil. The static resistance when two 6-volts coils are connected in series is the same whether or not you pay attention to + on one coil to ground, - on that coil to + on the other coil, and - to Tri-Spark (on positive ground bikes). However, the actual "resistance" is a combination of the resistance, reluctance, and capacitance of coils and it changes as the RPMs change. The engine will run no matter how you connect the coils as long as they are in series. However, there is a reason coils are marked + and - and they really need to be connected correctly!

I also had a guy with a Norton "heat" failure who was using a two-output 12-volt coil meant for a Harley. Nothing particularly wrong with that except that it had a 2.5 ohm primary and that's too low for Tri-Spark.

dynodave said:

1.


IF LUCKY
$48K new RAM 3500 diesel 9200 miles, ABS brake controller /pump/ solenoid pack craps out!!! And I don't really go around constantly locking up the brakes...14 days to get a replacement in. My new silver truck some of you guys saw at the rally in Michigan.

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Brace yourself for more of the same, if the Dodge /Cummins 3500s I'm familiar with are any indication.
My brother has had two in the last 8 years, many serious issues including 40%diesel in the oil every 3k miles, front end falling apart etc.
Neighbour has similar with his 2013 as do my Rancher friends with a 2015 and 17 in the BC interior.
They had a recall on the tie rod ends and parked one truck for 2 months waiting for parts. Then the replacement part was recalled!
He parks it in the barn since the sunroof leaks and the Dealer can't fix it.
I haven't heard a good report on Dodge full size trucks in a long time.

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