coils externally grounded?

[miked]

82 GS1100G, are the coils externally grounded via the mount points to the frame?

I'm having a wonky problem with getting the bike running and I'm trying to eliminate things. New Dyna coils are mounted, but not really well - just sort of place holders for the moment while I get the final tune in it, but need to be sure that I'm not ignoring a possible problem, figured I'd ask here

 

[slayer61]

The laminations in the coil don't need to be grounded. The coil will work just fine without it solidly mounted or grounded. Sonora? That's in my neck of the woods! Central valley, Lodi. Howdy neighbor!

 

[miked]

howdy neighbor - by "laminations" you mean the 2 "stacked metal" looking mount points at each end of the coil?

 

[rustybronco]

by "laminations" you mean the 2 "stacked metal" looking mount points at each end of the coil?

Transformer laminations...
http://www.google.com/imgres?imgurl...973Ub6XGJLC9gTsgIGoBg&ved=0CFYQ9QEwAw&dur=762

 

[miked]

yep, we are describing the same thing. Thanks

 

[Redman]

82 GS1100G, are the coils externally grounded via the mount points to the frame?

I'm having a wonky problem with getting the bike running and I'm trying to eliminate things. New Dyna coils are mounted, but not really well - just sort of place holders for the moment while I get the final tune in it, but need to be sure that I'm not ignoring a possible problem, figured I'd ask here

No. The ignition is not grounded through the coil mounting points. And then to discuss about what ground do the coils have:

First lets say that the what we call "a coil" is really two coils of wire. A low side coil and a high side coil. And both of these coils each have a wire on each end. None of which are grounded like you might think of being directly connected to a ground all the time.

The low voltage side (12vdc) has power (orange/white) on one wire all the time, and the other wire from other end of that coil goes to the ignitor (or breaker points) and gets switched to ground when needed. (actually when has been connected to ground and then when NOT connected to ground is when the high side coil makes a spark).

The high side (high voltage for spark, the spark plug wires), one wire goes to one spark plug electrode and other wire on other end of that coil goes to other spark plug electrode. And the plug bases are grounded by being threaded into the head.

Now the metal that goes through the coil is grounded by the fact that it is bolted to the frame, but that is just for mounting purposes, is not really part of the ignition circuitry.

>>later note:
I am speaking of Suzuki GS stock arrangement. Other systems have been different, and hi or low coil is grounded, and/or is electrical common connection between hi and low side.

I can not say anything about your aftermarket Dyna system.

.

 

[posplayr]

I just learned this a few weeks back, the high voltage current through the secondary that creates the dual spark plug firing actually completes the circuit through the two spark plugs in series rather that in parallel to ground.

Both plugs are connected to ground but they are passing current between then and not back to the coil as the coil is not grounded.

KoKar show this in his DIY ignitor thread.

http://www.thegsresources.com/_forum/showpost.php?p=1506459&postcount=29


Basically the current that is jumping the gap in one plug is the same current jumping the other gap; The current passes between then in the head which is really not acting like ground (to get back to the coil) as much as a connection between them. This insures that both plugs fire simultaneously.

If the coil were grounded, then there would be different currents jumping to ground at possibly different times.

 

[rustybronco]

I just learned this a few weeks back, the high voltage current through the secondary that creates the dual spark plug firing actually completes the circuit through the two spark plugs in series rather that in parallel to ground.

Correct....

 

[pdqford]

the high voltage current through the secondary that creates the dual spark plug firing actually completes the circuit through the two spark plugs in series rather that in parallel to ground.
>
(snip)
>
Basically the current that is jumping the gap in one plug is the same current jumping the other gap;

Exactly. This is called a "Waste Spark" ignition system used on many automobiles. One spark plug fires from the center electrode to the side electrode and the other plug fires from the side electode to the center electrode. (Thats why you should use a double platnum plug in this system if you don't know which plug is firing in which direction. The manufacturer will actually install a center plat or a side plat single platinum plug in the proper hole.)

Waste Spark does make it difficult to analyze the secondary for any one cylinder because the scope will basically see the average voltage for both cylinders, one firing under compression and one firing on the exhaust stroke.

 

[Redman]

.....
Both plugs are connected to ground but they are passing current between then and not back to the coil as the coil is not grounded.

.....
Basically the current that is jumping the gap in one plug is the same current jumping the other gap; The current passes between then in the head which is really not acting like ground (to get back to the coil) as much as a connection between them. This insures that both plugs fire simultaneously.......

Yes, I was trying to think of a way to describe that, but ignored it.

So, we should not really say the plugs are grounded. They are connected to what is the ground, but they aren't there to be grounded (in scence that the ground is connected to the battery negative). Both plugs are in the head and the head serves as a common point.
Another way to say it; the high side circuit is this: one end of coil, that plug wire, that plug cap, that plug, that plug gap, thru the head, the other plug gap, the other plug, the other plug cap, the other plug wire, to other end of the coil.
Another way to say it: The high voltage that is produced is beteween one end of the coil and the other end pf the coil. Could almost say that one plug wire is positive and other plug wire is negative, and the current flows from one to the other thru the two spark plugs in series with the head being what connects the two plugs together.

.

 

[pdqford]

Right ! And if you are trouble shooting, checking for a spark, you really need to have the companion plug connected. But if you have no sparky on say cyl #1, it might be because cyl #4 is the problem.

 

[posplayr]

Exactly. This is called a "Waste Spark" ignition system used on many automobiles. One spark plug fires from the center electrode to the side electrode and the other plug fires from the side electode to the center electrode. (Thats why you should use a double platnum plug in this system if you don't know which plug is firing in which direction. The manufacturer will actually install a center plat or a side plat single platinum plug in the proper hole.)

Waste Spark does make it difficult to analyze the secondary for any one cylinder because the scope will basically see the average voltage for both cylinders, one firing under compression and one firing on the exhaust stroke.

Yes I knew it was "wasted spark", which I assumed was because of firing on the exhaust stroke as well as compression stroke. But I did not realize that that also meant that both plugs complete the same high side circuit or are these two things separable?

 

[posplayr]

Right ! And if you are trouble shooting, checking for a spark, you really need to have the companion plug connected. But if you have no sparky on say cyl #1, it might be because cyl #4 is the problem.

Oh, that explains a lot as well.