a question about wiring's affect on spark

Art Vandelay /

Feb 01, 2021 09:09PM

Ok this is a real noobie question....

I tore down my Califfo moped to paint, put it back together, and now it won't start. I have spark. My switch is in rough shape, and I think my tail light is burnt out. So there's a chance my wiring is problematic.

However.... if it was an issue with wiring (switch or whatever) this would kill my spark, correct? It should have no impact on the bike actually starting and running if I see a good consistent spark? As in they are independent of each other?

Thank you for any insight!!!

Re: a question about wiring's affect on spark

Nick MBC /

khool1499

Feb 01, 2021 09:28PM

Observing spark outside the cylinder isn't exactly a guarantee its sparking inside the cylinder.

It's kinda like if fuel is flowing out of your fuel line then you know you have fuel flow, and you have a clean carb, but the petcock could be kind of clogged and the bike won't stay running because it's not getting enough gas.

Make sure you keep a plug in the bike then check for spark with another external one. Sometimes a bike has great spark with no compression, when the flywheel can spin fast easily but once the resistance from the compression is there it loses spark. This could be caused by a bad ground from painted frame, for example. Grind off the paint where the electrical will be grounding.

Re: a question about wiring's affect on spark

Dirty30 Dillon /

hydra

Feb 01, 2021 09:43PM

If your rotation speed is killing the spark, that's an electronic issue not a mechanical because of the compression.

Compression does effect spark in that it is harder for a spark to jump a gap in compression . Often a sparking plug that seems fine against the head, will be a dud under compression.

That said, if you have true spark, than the wiring won't stop something from running.

Re: a question about wiring's affect on spark

Nick MBC /

khool1499

Feb 01, 2021 10:02PM

> Dirty30 Dillon Wrote:

> -------------------------------------------------------

> If your rotation speed is killing the spark, that's an electronic issue

> not a mechanical because of the compression.

>

> Compression does effect spark in that it is harder for a spark to jump a

> gap in compression . Often a sparking plug that seems fine against the

> head, will be a dud under compression.

>

> That said, if you have true spark, than the wiring won't stop something

> from running.

Yeah that's what I'm saying, test the electrical system under load (compression) and if there's no spark it's likely a bad ground or corroded points. A bad ground is almost a wiring problem.

Re: a question about wiring's affect on spark

🇮🇹💦 Of the Loin /

Go to branch

maitland

Feb 01, 2021 10:34PM

simply changing the ohmic resistance of your spark plug line by 1 ohm, doubles the amount of energy required to obtain the same amount of energy.

Re: a question about wiring's affect on spark

Art Vandelay /

art_vandelay

Feb 02, 2021 06:07PM

Thanks for the information.

The thing I'm stuck on is why faulty wiring would have any affect on spark at all? Isn't it usually one coil generates current to the spark plug and the other to the accessories? Or have I got that wrong?

Re: a question about wiring's affect on spark

Brian F /

Go to branch

brianf

Feb 02, 2021 06:15PM

Your kill switch is in the ignition circuit, and depending on the bike and wiring your brake light may be as well.

Re: a question about wiring's affect on spark

pat splat /

ggspeed

Feb 03, 2021 09:02AM

> Art Vandelay Wrote:

> -------------------------------------------------------

> Thanks for the information.

>

> The thing I'm stuck on is why faulty wiring would have any affect on

> spark at all? Isn't it usually one coil generates current to the spark

> plug and the other to the accessories? Or have I got that wrong?

its u that does not comprehend. Stare at a wiring diagram and scratch your head

Re: a question about wiring's affect on spark

Nick MBC /

khool1499

Feb 03, 2021 09:06AM

> Art Vandelay Wrote:

> -------------------------------------------------------

> Thanks for the information.

>

> The thing I'm stuck on is why faulty wiring would have any affect on

> spark at all? Isn't it usually one coil generates current to the spark

> plug and the other to the accessories? Or have I got that wrong?

How is electricity transferred? Wiring, right? So how would wiring NOT affect spark? If you have no wires, how would you have spark? I don't get your question.

If you don't have a wire connecting the ignition circuit to ground, for example, you won't have spark

MOPED ARMY

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