Coil Problems

A riding friend has had 2 occurrences of coil failure. The first occurred about a year and a half ago - the coils (Trispark) were a few years old so he bit the bullet and ordered a new pair from Trispark.
The second failure occurred on the weekend where one of the 18 month old coils went open circuit. The other was reading about 25% higher resistance than recommended.
The response from Trispark was that he must be "crimping" the coils. It was true that there was evidence of some slight oiling around the top of the failed coil, but no other damage.
He is using the stock (OEM) method of mounting the coils (see generic photo below)

My questions of forum members are:
1. Has anyone experienced repeat coil failures - and what did you do about it?
2. Are there any known problems with Trispark coils?
3. Has anyone made changes to the OEM coil mounts to be "gentler" on the coils?

Thanks in advance
Cheers

Those clamps must be not tight at all , as in like 2 lb. torque value , or just snug. The danger is potential crushing to the thin aluminum coil bodies. If one is leaking any fluid It's too late . My Trispark 6 V. coils work great at snug only , no more. Same for Lucas coil mounting.

Agree on coil brackets being just tight enough to hold coil and no more. Could also be a vibration problem. I've had a modern aftermarket Pertronix coil die on my classic Mini, likely from vibration. My Commando's original 48 year old Lucas coil still going strong despite evidence of over tightening brackets , crushing outer casings slightly.
Is this bike running points or EI? Can something wrong on points (condenser?) Harm the coils? What about an over voltage from a failed Reg (zener)?

Tornado said:

Is this bike running points or EI? Can something wrong on points (condenser?) Harm the coils? What about an over voltage from a failed Reg (zener)?

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It is EI (Trispark) - but the problem is definitely coil. Put a pair of old coils on and it runs.
Most probably over tightening. Looked at the OldBritts torque chart - 0.8 ft lb (10 in lb) - that's very low!
Cheers (and thanks for the replies)

robs ss said:

My questions of forum members are:
1. Has anyone experienced repeat coil failures - and what did you do about it?
2. Are there any known problems with Trispark coils?
3. Has anyone made changes to the OEM coil mounts to be "gentler" on the coils?

Click to expand...

1. No.
2. Definitely no. They are excellent.
3. In almost 50 years of Norton'ing I've had only one coil failure and it was a result of over tightening the clamp. As has been mentioned, use only enough torque to hold them snug.

I use small washers in between the coil holder body while threading the bolts so as not to crush the coil but just hold it from moving.
My nickle in the grass.
Cheers,

A dab of threadlock would help hold the bolts in the mounting bracket without needing to be over tightened.

Three years ago I completely rebuilt a T160 for a friend of mine. He has had one of the three Trispark coils which I fitted fail. On Tridents the coils are held by a large grommet which can't crush the coil. Obviously, Lucas, Bosch, & any other make of coil can fail just the same. Two of the PVL coils on my Hinckley Trident failed one after another.

Martyn.

Tornado said:

A dab of threadlock would help hold the bolts in the mounting bracket without needing to be over tightened.

Click to expand...

Yep - used 243 (blue)

robs ss said:

Yep - used 243 (blue)

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The way the bracket clamps work seem to encourage over tightening just to hold the bolts in the welded nuts.

You could make clamps a bit bigger/wider and rubber inserts to protect the coils maybe, I had 2 coils fail while on my Commando because of the brackets when I built my Featherbed/Commanondo I cut 2 holes in the tool tray and rubber mounted my coils hanging in the holes, never had a coil fail after that for over 30 years, but now with the JH maggie no normal coils the coil is inside the maggie, where I cut the 2 holes in my tray I cut them out where I now have a very small battery mounted for brighter brake light and head light if I ever need to use it.
So if vibration is the cause then rubber mounting could be the answer, if the coils aren't tight enough they will move in the mounts, but tightening them also has its problems.

Ashley

I have only had one original 40+ year old coil fail on my commando
And one coil failure on my Indian Enfield
One thing I would add is I have seen many Lucas coils crushed by owners overtightening the clamps on commandos but most just keep going !

Worries about MA6/MA12 coils being crushed can be put to rest by fitting a dual output coil as sold by CnW and others.

Those 45 mm coils _are_ a signature mark on the Commando, but .... after a long debate with myself I have decided to let function dictate form / looks.

The more I look at those stock coils, the more I dislike their crude mounting..

- Knut

mdt-son said:

Worries about MA6/MA12 coils being crushed can be put to rest by fitting a dual output coil as sold by CnW and others.

Those 45 mm coils _are_ a signature mark on the Commando, but .... after a long debate with myself I have decided to let function dictate form / looks.

The more I look at those stock coils, the more I dislike their crude mounting..

- Knut

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Yep - I agree, and have dual output on mine.
Can't spend someone else's money though...

mdt-son said:

Worries about MA6/MA12 coils being crushed can be put to rest by fitting a dual output coil as sold by CnW and others.

Those 45 mm coils _are_ a signature mark on the Commando, but .... after a long debate with myself I have decided to let function dictate form / looks.

The more I look at those stock coils, the more I dislike their crude mounting..

- Knut

Click to expand...

I’m still into looks Emgo coils work great are inexpensive and look like Lucas.

One of the reasons we do mods/upgrades on our bikes to get things right, I have no problems with going away from original if it works better, but then I went right away from original early on.
Keeping a bike in concourse condition is ok if you were showing it and not riding it, but there are so many good upgrades to be had if you do ride your bike and having brakes that do work, when I bought my 850 new wasn't long before factory parts or things failed, after warranty ran out chrome on the rims started to lift, paint work on the tank crazed and cracked (no undercoat under the stock paint job), just small things that cost a lot of money to fix, Akront alloy rims fixed the peeling chrome and a decent painter for the tank done right, but should have got more than 2 years out of them and the bike kept out of the weather didn't help.
I did get a warranty job from the crack oil tank but only on parts replacement and not labour charges (1 year warranty on parts but only 6 months labour warranty), I told them where the oil leak was coming from the oil tank (the dreaded bottom bracket) but they still charged me 3 hours labour they said they couldn't find where the oil leak came from, they never got to work on my bike ever again and told them so.
Coil brackets over tightening them does damage them but if you don't tighten them a bit more they do get lose from vibrations and move a bit.

Ashley

I snapped this photo from the Olfield/Slark interview when they were panning the Mark 3.
1. Notice how the offset of the coil and wire roll to outside on the horizontal.
I've always had them top side.
2. Zoom in and notice the gap on the coil clamp. Brian says this bike is right out of the crate.
Obviously, the factory did not close the gap..

MichaelB said:

I snapped this photo from the Olfield/Slark interview when they were panning the Mark 3.
1. Notice how the offset of the coil and wire roll to outside on the horizontal.
I've always had them top side.
2. Zoom in and notice the gap on the coil clamp. Brian says this bike is right out of the crate.
Obviously, the factory did not close the gap..

View attachment 101404

Click to expand...

Thanks Mike
You either have a higher resolution photo than this (as posted) or much better vision than I (maybe both!)
At full zoom I can't clearly make out the gap you're referring to.
Cheers

I've been running the original style coils since 2006 when I bought a pair from Old Britts and ditched the Boyer and the single ignition coil that was on the bike when I bought it. I think the OB coils were German-made but I'm not sure. Never any issue with them, just tightened them to "snug," no idea how tight they actually were but never an issue with the fittings loosening or the coils shifting.

I'm one of those folks who see the coils as a major part of the look of a Commando so there is no way I would eliminate them and 16 years of use has given me no reason to do so anyway.

A double-ended coil off a CB750 Honda probably does not look right on a Commando ? But it has fewer connections and its mount is not a stupid clamp. Joseph Lucas Prince Of Darkness ?