Coil Ground

[Rottweiler]

Does the coil need grounded? I believe so? Found a bolt missing on the coil cover The center one that goes to the frame.

 

[Iman]

get that bolt replaced asap

 

[Rottweiler]

Does any one know what size bolt? Is it standard thread?

 

[BWG56]

Isn't that the top motor mount? Hard to tell with the pic

 

[Mr. Wright]

I believe it's a 5/8-24, if I remember right. It's a very short bolt, so make sure it's tightening the bracket, and not bottoming out in the hole.

 

[BigDogBro1]

If it's the upper motor mount bolt then it needs to be replace before riden again.
Not sure if it needs to be a grade 8 bolt but I would check.

 

[BBChopper]

Isn't that the top motor mount? Hard to tell with the pic

Yes, but I think it depends on what frame you have size wise...
It also looks broke off?

 

[claw]

On the '08 its a 1/2" dia. bolt Don't know about the '04.

 

[Rottweiler]

The bike is a 2004. No it is not broke off. I just didn't have any that big on hand. Very hard to tell if it was fine thread or not? Does this also ground the coil? I will not ride it until it is replaced. I am also having electrical gremlins?
Thanks for the feedback.

 

[spadesluck]

Coil only has 3 wires going to it. The middle one being the 12v source and the other 2 are for each plug wire to send spark to the cylinders. No ground wire.

 

[bearman]

….. Does this also ground the coil…..

NO.

The coil cover is still bolted to the heads, which would eventually be grounded through the starter, but if the coil was grounded, it wouldn’t work.

The way the coil works is that you have one 12v positive wire feeding both the high and low voltage side of the coil (connected internally). What happens is that the ignition module triggers a very temporary ground on the low side of the coil, which induces voltage in the high side of the coil and this high voltage jumps to ground through the spark plug.

So the coil actually grounds through the wires to the ignition and the big wires to the spark plugs.

 

[DRBarnhart]

I would like to make a correction...

The way the coil works is that you have one 12v positive wire feeding both the high and low voltage side of the coil (connected internally) and a ground from the ignition module to the low voltage side (primary) of the coil. While current is flowing in the coil the primary windings build up a field. What happens is that the ignition module triggers a very temporary OPEN on the low side of the coil, which induces voltage in the high side (secondary) of the coil and this high voltage jumps to ground through the spark plug.

So the coil actually grounds through the wires to the ignition and the big wires to the spark plugs.

A small change but important...

Dennis

 

[bearman]

You are correct, I made a mistake. It is a temporary open that makes the coil fire.

 

[BigDogBro1]

When the ignition points open the coil field collapses and discharges through the sparkplugs.

 

[DRBarnhart]

When the ignition points open the coil field collapses and discharges through the sparkplugs.

Isn't that basically what we said?

Or, another way to put it...

When the ignition points open the primary coil field collapses inducing voltage in the secondary coil windings and that voltage discharges through the sparkplugs.

Something to do with Faraday's Law of Electromagnetic Induction. :up:

My brain hurts... :bang:

:lol::lol::lol:

Dennis

 

[Rottweiler]

Thanks guys. On my 2004 it is a dual fire coil just two wires. I don't believe there is a problem anyway just hoping I found the gremlin. Bike has been nothing but a pain since I got it. Both ehc's light up the Ignition fault light when the run button is pressed. Other times just four way flasher and all but two fault light on. Next time bike runs. Yes I have a multi meter, Just need more patience.

 

[BWG56]

Was it the bolt to the upper motor mount???

 

[Rottweiler]

Yes it is the top motor mount bolt. looks like 1/2 inch fine thread. 1/2 coarse does not fit. I will get a grade 8 bolt. Still looking for electrical issues! Can't find what causes only four way flasher yet. Replaced back bone wire harness and back light wires, been checking everything with ohm meter. Did not like the inputs from the handle bars, could not get any button the read less then about 750 ohms. Also all headlight wires read something to ground. Not sure if this would cause power up fault?