ignition coil smoking on 1980 GS400

[dbill]

Just bought a 1980 GS400L with electrical problems and am trying to get it working.
- bought a new battery - fully charged.
- with the key in and ignition switch on, the left ignition coil is smoking and getting hot.

Based on research I've done on this site and looking at a Haynes manual I thought this bike would have all electronic ignition, but I noticed that it uses points ignition. It seems to me that I need a new ignition coil, but I'm wondering what is causing this coil to heat up and smoke? Is there something else that is damaging the coil?

Any help would be appreciated.

[pete]

I'm far from a guru on this stuff, but given a coil is, well, a coil... I would suggest it possibly has a short or something in there, so I would definitely replace it.

It's been years since I played with resistance etc. but in theory you should be able to measure the resistance across the coil to see if it has a short, and if it does it would read a low resistance compared to what it should have.

I hope that makes sense and I'm not leading you up the garden path...

[tom203]

Is this a 400, 425, or 450 model? doublecheck date/model on steering stem?
If points and they are sticking closed, the connected coil could get very hot. Check resistance of both coils and compare.

[SVSooke]

If the OP is in Canada it's a 400.Had a couple,same body work as a 450 with a 400 TSCC 8 valve engine.

[dbill]

Thanks for the input. I checked the resistance in the coils, the problem one has a resistance of about 1 ohm and the other has a 5 ohm resistance.

I can't find one that looks like it. Someone told me that I can use any coil that has two wires coming in. Is that true?

The bike is a 1980 GS400, bought in Canada. The serial number starts with GS40X.

[pete]

Ok now I'm a little confused...

I can't see a model anything like that on www.alpha-sports.com, but I would imagine a coil from a similar model GS450 would suit maybe? Not really sure though as the 450's of that age didn't have points.

Someone who knows that Canadian model may need to chip in here...

[dbill]

One other question. I'm trying to adjust the timing now that I've adjusted the points. I'm trying to get the markings right on the flywheel.

Besides the F and T, I also see an L on one side and an R on the other side. Does the R refer to the right Cylinder? If so I'm assuming that when the flywheel is turned to where I see the R, that the points that are linked to the right cylinder should be making contact. Is that correct? I'm trying to make sure I don't have my wires going to the ignition coils mixed up.

[tom203]

Does this help? Does yours look similar?