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Old 12-21-2009, 10:09 PM
speedster239 speedster239 is offline
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Default Re: Electrical System Questions!

So, is the current flowing from positive to negative or negative to positive? Is what we label as positive on the bikes and most automobiles truly that what you guys are saying?

This seems important because I know that if the current were flowing from the frame, instead of to it, the capacitor would not charge/discharge into the coil and no spark would take place...

Can you see my confusion?

Last edited by speedster239; 12-21-2009 at 10:12 PM.
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Old 12-21-2009, 10:39 PM
TheE TheE is offline
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Default Re: Electrical System Questions!

The electrons technically flow from the - terminal of the battery to the + terminal, so they're correctly labeled. It's a bit strange to have the current flowing from the frame, but you should be able to analyze the circuit with both methods and get the same results. It's just a question how we assign arbitrary labels to things, really.

When lightening strikes, the bolt you see is coming from the ground and going back up to the cloud. Trippy 0.0
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Old 12-21-2009, 10:52 PM
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Evan Evan is offline
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Default Re: Electrical System Questions!

Definately right about the Lucas electric thing...........I had a Jaguar once. OMG! What a mess!
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Old 12-22-2009, 12:08 AM
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wjliebhauser wjliebhauser is offline
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Default Re: Electrical System Questions!

Like the man said, it's a waste of time to fuss about which way electrons are flowing in a DC system like a car or bike. It is a closed system, i.e. confined to the bike (or car), and electrical gizmos only operate when the circuit is complete. Same with where the fuse goes; the convention is to put them in the + side, but if you put them in the circuit between the gizmo and the frame, instead of the gizmo and the + lead, the result is the same. People often use the 'water in a pipe analogy' to explain electricity flow, but it is only partially valid, and thinking of electric current like it's water in a pipe can lead to ideas that are all wet... Electricity is not water. The theory behind English cars with + ground to frame was that there would be less electrolysis and corrosion. Good idea, but in practice, it ended up as useful as the old theory that lug nuts on the left side should be left hand threads to stay theory, but not worth the effort in real life. Also, DC and AC act differently, so even all current is not the same; on AC, switches and fuses MUST be on the 'hot' or supply side to prevent YOU from being the gizmo if you touch something that is grounded. Luckily, not much chance of dying messing with a Chinese bike motor!

"Captain Easy"
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Old 12-22-2009, 04:29 PM
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2door 2door is offline
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Default Re: Electrical System Questions!

My first question would be why do you need to know the direction of current flow? The point is moot however in terms of the ignition system of a Chinese 2 stroke engine because we're dealing primarily with A/C, alternating current, which flows both ways. Hence the name, 'alternating' current. Forget the bicycle frame. It has nothing to do with the circuit that fires the spark plug. The ignition system of your engine would function even if your frame were made of wood, as long as it is wired correctly. The only time the bike frame would come into play would be if you were using it as a ground to kill the engine through the kill switch; and then you'd need a good connection, no paint or rubber between the engine case and the frame's metal or a ground wire from the switch to the engine. There is another misconception that you might need to know about. The kill switch does not open the ignition primary circuit when depressed. It in fact closes a circuit between the black wire, (the engine ground wire) and the blue. Or if you prefer the white and black wire of the engine case (or bike frame if there is a good electrical connection between it and the engine). Forget about what you've been taught about electron flow. It has no bearing on your ignition system. Now let me confuse things. I use a battery (D/C power source) to power my lights. I run a wire from the battery negative terminal to a place on the bike frame, then run a wire from the positive terminal to a switch then out to the head/tail lights. I either ground the lamps/socket to the light case which is attached to the frame or a seperate wire from the lamp socket to the frame. The frame then becomes the conductor. This allows me to run a single wire to my lights instead of two wires; saves wire and looks cleaner. Hope these replies helped you and answered some of your questions.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"
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