Fried coils le mans

I left the ignition on the bike turned on and was called away. Forgot to turn it off…When I came back the coils had heated up and are not now producing spark!There’s a waxy substance coming from so I guess they are toast!.:frowning:… Forgive my ignorance with all things electrical but have I missed a wire or something when rewiring? The t3 coils heat up to if left switched on. I have a spare set of 6v coils I got with the bike so going to put those in(if they work). Help

Afraid that what happened can happen if you leave your ignition on without allowing the coils to discharge by sparking.

Thanks Ian. Lesson learned. I will try the spare set.

Unless you are running with a Lucas Rita system, the 6V coils will probably not be any good for you.
Normal T3 coils will be rated at 12V, get them from VWP for a few quid each

Thanks Don. Its got a Lucas rita ignition on it hence the 6v coils. I tried the spare set and no luck either but I am getting a spark when I flick the kill switch on and off. This would mean the coils are ok?? Any ideas?

Do you get a spark when you disconect the 2 pin plug?I have a check list at home I will try to bring in tomorrow.

No Ian, no spark when I disconnect that…do you reckon the amplifier is damaged?

this may help you

Thanks GB, but I already had it wired up and running. Surely same has happened to someone, leaving ignition on and overheating coils, what harm is done to amplifier in such a case and how to test?

Can’t see why the amplifier should be expected to work normally but mustn’t be left on without making any sparks. The amplifer waits for a signal, makes a spark, waits for the next signal, etc. Waiting indefinitely is just less work to do. The coils do get bluddy hot normally, a typical 12V of 3 Ohms will be about 50 Watts, that’s burn your fingers hot, 2 x 6V in series not so bad for each, 25 Watts, still flippin’ hot thought and bear in mind they’re pretty much like that all the time the bike is running. Depends where they’re located but if under side panel there’s not that much ventilation really. Think about a car coil which is right by a hot engine and with virtually naff all any cold air, still has to work. So not sure what is going on here.

That is Mistral’s basic test and it means the coils and the output stage (at least) of the amplifier are working. Maybe an input problem. You can excite the pick-up by touching the pole piece with a screwdriver blade or something like that. The input 2-pin plug can I think have dirty contact problems quite easily, oxidised contacts etc., the input current is very small so this connector must be virtually perfect. I wrap mine in gaffa tape and a small cable tie to make sure no damp gets in. HTH

Advice from Lucas Rita (John Carpenter?) in 1991 on how to test.1. disconnect pickup from amp.2. open old pair of plugs to 300 gap and lay on top of cylinders.3.system should spark everytime ignition is switched off. Also when female (white/purple) is shorted to earth.4.Resistance across pickup 250-400ohms and neither side should go to earth. coils. 6 ohms across HT. 2 ohms across LT.Any more and they are toast. People hold onto old coils because they don’t believe that an extra 0.5 ohm is enough to toast them but it is.Obviously you need a good meter but that should not be a probel today. Incidently my problem was swarf shorting out the lhs plug which was not apparant using points.
iandunmore2013-11-06 08:19:59

Thanks Ian and Mike. Got a good meter and tested everything and all was ok…My new battery was reading under 12v so hooked up to the car for further testing and got a spark back in plugs! Even though the battery was brand new it wasn’t optimum and needed a charge. It would crank the bike but not produce a spark at the plugs so all ok now! Please forgive my stupidity and thanks for the help. If nothing else I have learned a fraction about electronic ignition

That is a good post as it is worth remembering that electronic ign and RiTa in particular need a real good battery low volts and it will not fire up, Pleased you got it sorted.

Worth also noting the Lucas RiTa connections do get mucky it is the only time mine caused a problem I subsequently sealed the connectors with silicone, brilliant stuff I go around all the 12way/15 way and the RiTa ones about this time of year clean off the old silicone, clean the connectors then re seal them.

Agree with above. About 8 years ago my lemon died on the way to work. Tank off, pulled both connectors apart and pushed togetrher again, ran fine.Bought some cotact cleaner on the way home and did the job properly. BTW, if fitting new handlebar rubbers spray the inside with conract cleaner. They slide on easily and then grip like the proverbial when it evaporates.

Thanks guys for the sage advice. I’ll post a few pics of the bike when I’m finished.

Thank goodness for that. Simply the battery not enough oomph… This year when I rebuilt mine I discarded the 5-pin plug block as the brass (?) pins and sockets were looking very dull and didn’t seem to want to clean up, so instead I cut it off and soldered on longer lengths of wire with new 1/4" blade connectors, one less set of contacts to go wrong.