Grounding Hogs Day

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davem222

davem222
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Hey guys,
As some of you may recall, I recently, and idiotically, burned out my Pamco for my new build by not grounding the circuit (sigh). So I've got my new Pamco in hand and am a bit trigger shy lol. Quick question: can I simply have one ground going to the engine (to the bolt on the top of the bottom end, directly below the carbs) and all of the grounds tied into that, or do I need everything grounded separately? I would really REALLY like to not screw it up again, lol. Thoughts?
Also, as a side note, how does the engine or frame constitute a "ground"? They're separated from the earth by an insulator, rubber tires. What am I missing here theoretically?
Thanks guys!

Dave

PS: I'm attaching my wiring circuit fyi, please note that the ground from the PMA is a mistake and I know it :)
 

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For automotive purposes, "ground" is the return to the battery. If you'll look, the negative side of the battery is attached to the frame.

Attaching a wire to any part of the frame is the same as attaching it to the negative side of the battery. A common saying when I was attending Basic Electricity and Electronics school: "Ground is ground is ground" meaning it doesn't matter WHERE it is physically, all grounds are electrically the same point.

Most parts that are mounted with rubber for vibration control have a jumper wire from the metal shell to the frame somewhere. That's why there are separate ground wires for the turn signals - to get around the rubber mounts which insulate the turn signal shell from the frame.
 
imho you do not need to be grounded to earth ground. minus cable from battery to frame acts as "local" ground. frame with engine just work together as "zero potential" wire. also some switches use their enclosure as "zero" contact. you just always have everywhere minus from battery(if you have ground) - it means one wire less for every circuit on your bike...
 
See, that's what I thought re: local ground, I wired the whole thing up to the neg terminal on my battery and the Pamco soon stopped producing a spark. I was told by people on here that I probably fried the thing that way. Lol, now I am completely in the dark ha ha ha. Hugh definitely mentioned wanting to attach the battery neg to the frame or engine. Perhaps that's so there's no voltage build up and then an arc between them, which could possibly fry something? I dunno.
 
Btw, by "I wired the whole thing up to the neg terminal on the battery" what I mean is that I did not connect the neg term to the engine or frame, just used the neg term as my ground.
 
You need a ground from your negative terminal on your battery to the frame/engine in order to get a spark at the plug... The part the plug wire goes onto is the positive terminal and the part that screws into the side of your engine is your negative ( ground electrode ) with the porcelain insulator in between the two ... If you don't complete the circuit then no spark... The engine connects to the frame -> frame connects to negative terminal on the battery -> everything is happy go lucky :) ...

SparkPlug-Condition.gif



Also it is not widely known but DC ( Direct Current ) electric current flows from negative to positive,,, not the other way around,,, while in AC ( Alternating Current ) it flows both directions... With motor vehicles we deal in DC ...

I hope that helped :)
 
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That's rad Dave, thanks, I think I get it now (sorta). If the neg bat terminal isn't the same potential as the engine, then you're really running 2 circuits, which could result in a big pot diff between the neg term and the engine, which would lead to bad things. Anyone have any thoughts as to whether I should ground the different items separately?
 
I am running negative switched relays in my setup and have multiple grounds... Think of the frame as one big piece of wire that you can tap into multiple places to help complete your grounding circuit back to the battery...

Here is an example using my frame picture :
full


I hope that helps :)
 
As stated, you need to run a ground wire from the negative battery terminal to the engine to get spark and allow the electric starter to work.
As for other grounding, I support the "bring it back to one point"solution.
This helps prevent having to hunt down "bad grounds"somewhere on the frame that have become loose or corroded.
Downeaster...ground is ground is ground until you start wiring audio systems for studio and live production.
Gets a bit more interesting then :)
 
KeithB said:
Downeaster...ground is ground is ground until you start wiring audio systems for studio and live production.
Gets a bit more interesting then :)
Click to expand...

I imagine. Been a lot of years since I was involved in installation and maintenance of "ground planes" as they apply to radio frequency interference, Faraday cages, TEMPEST requirements and Secure Compartmented Information Facilities (SCIF's).

As to the "one ground" solution, there's something to be said for only having to inspect/maintain one ground point, but there's also the factor of all the extra wire and crimped/soldered connections required to achieve a single ground point. I suspect it's a case of six of one and a half-dozen of the other.
 
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I run any ground wire from a unit the shortest distance possible to a good chassis ground. If you have an isolated "earthing station" as they are called in some cultures, you don't have to "hunt" for ground issues for long on an inoperative or intermittent system, as it is close by. You check that one, from the main to that location, the location to the component and the main one from the battery to the frame, and you are done with the ground side.
May not be as "clean" installation wise, but pretty does not often mean easy to work on.
 

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