Could my coil drain my battery, why?

Rook32432

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When I remove the points wires from the harness connecting to the coil, I get 12v+ at the coil. Would this indicate my points are somehow causing a voltage drop via a short, or am I still dealing with a coil issue? Please forgive my incompetence.
 

Jim

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When I remove the points wires from the harness connecting to the coil, I get 12v+ at the coil. Would this indicate my points are somehow causing a voltage drop via a short, or am I still dealing with a coil issue? Please forgive my incompetence.
Also if I disconnect the right side points wire and leave the left connected there is no loss in voltage.
The points are nothing more than on/off switches. In a 360° motor, one is open and one is closed.... and there's prolly some overlap there where both are open, but I digress...
With the way you've wired your engine, with one of the points (switches) closed, there's a path to ground that energizes the coil. Disconnect that one and the coil doesn't pull any power from the battery. That's pretty much what you're seeing.
 

arcticXS

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The points are nothing more than on/off switches. In a 360° motor, one is open and one is closed.... and there's prolly some overlap there where both are open, but I digress...
With the way you've wired your engine, with one of the points (switches) closed, there's a path to ground that energizes the coil. Disconnect that one and the coil doesn't pull any power from the battery. That's pretty much what you're seeing.
Jim, having 2 points really makes no difference to having 1 set that happens to be closed. The coil will never draw more than around 4 amps in any case. What the OP is describing must be a much higher current, unless his battery is much smaller than stock. Even a 5Ah battery shouldn't drop straight down to 6V when a 4A load is switched on.
I can only see 3 possible explanations to this:
- A shorted wire somewhere, which normally should result in a broken fuse or burned wires.
- One or more problems related to alternator stator/ rotor or rectifier/regulator, making them draw a current m
- A very small battery is being used. Something like an alarm battery, that is unable to even power a 3 ohm coil.
 

Jim

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Jim, having 2 points really makes no difference to having 1 set that happens to be closed. The coil will never draw more than around 4 amps in any case. What the OP is describing must be a much higher current, unless his battery is much smaller than stock. Even a 5Ah battery shouldn't drop straight down to 6V when a 4A load is switched on.
I can only see 3 possible explanations to this:
- A shorted wire somewhere, which normally should result in a broken fuse or burned wires.
- One or more problems related to alternator stator/ rotor or rectifier/regulator, making them draw a current m
- A very small battery is being used. Something like an alarm battery, that is unable to even power a 3 ohm coil.
Agreed.
 

Jan_P

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Here is my wiring diagram and the tcbros instructions I yoinked for reference. Forgive the sloppiness, I’m drawing from memory at work. Unplugging the wire from the ignition to the fuse plate then key on, the battery held its voltage steadily increasing from the drained amount. Plugged the ignition wire back into the fuse plate then keyed on and the voltage immediately dropped to roughly 6v.

Removed the charging wiring only, and still with ignition wired up and key on the voltage came back down to roughly 6v.


EDIT I was to slow
I would consider Disconnect the condenser from ground and see if it changes anything
Then disconnect the power feed to the points see what happens

1690629334556.png
 

Jan_P

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Also if I disconnect the right side points wire and leave the left connected there is no loss in voltage.

Points are tricky cleaning Inspection and measurement resistance to ground .. perhaps shift left to right feed
replace point
 

arcticXS

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Points are tricky cleaning Inspection and measurement resistance to ground .. perhaps shift left to right feed
replace point
Points will not cause a massive drop in battery voltage, as long as there is a coil primary winding between battery and points. This suggestion is just confusing.
 

Jan_P

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Points will not cause a massive drop in battery voltage, as long as there is a coil primary winding between battery and points. This suggestion is just confusing.

Maybe wrong maybe not there is a difference left to right and it is a common fault finding technique in Circuits which have two sides
HiFi amplifiers and so. perhaps not here.

#24

Also if I disconnect the right side points wire and leave the left connected there is no loss in voltage.


One can think it out ---Or one can test it out .Testing can involve procedures that does not give the desired outcome.
aka one unnecessary test but that is how I do it.
.
Points are problematic or was wen I had them A shop would most likely replace both immediately.

Feel free to do something else Sometimes it is difficult to find a fault cold when appears only warm ..

its not the battery if it goes low only when right side point is there The way I see it. Not necessary the whole , truth since a larger circuit is connected with both. It can still drop the battery.
but I would assume a fault on the right side Point and wire for that

Picture of Coil ??
 

mike in idaho

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When I remove the points wires from the harness connecting to the coil, I get 12v+ at the coil. Would this indicate my points are somehow causing a voltage drop via a short, or am I still dealing with a coil issue? Please forgive my incompetence.
With the points wire disconnected, what you measure at the 12v coil connection will be open circuit voltage which means very little, a single strand of wire will carry 12 volts if there is no load on the circuit. Plug the points wire back in and attach a length of wire to the battery post, touch the end of that wire to both sides of the fuse box while watching your voltmeter. Then poke the wire into the backside of the ignition switch connector, the power in terminal and the power out terminal. Finally probe both sides of the kill switch connections, inside the headlight.
 

Rook32432

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Maybe wrong maybe not there is a difference left to right and it is a common fault finding technique in Circuits which have two sides
HiFi amplifiers and so. perhaps not here.

#24

Also if I disconnect the right side points wire and leave the left connected there is no loss in voltage.


One can think it out ---Or one can test it out .Testing can involve procedures that does not give the desired outcome.
aka one unnecessary test but that is how I do it.
.
Points are problematic or was wen I had them A shop would most likely replace both immediately.

Feel free to do something else Sometimes it is difficult to find a fault cold when appears only warm ..

its not the battery if it goes low only when right side point is there The way I see it. Not necessary the whole , truth since a larger circuit is connected with both. It can still drop the battery.
but I would assume a fault on the right side Point and wire for that

Picture of Coil ??
IMG_5653.jpeg
 

arcticXS

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The battery I am using is a Duralast gold agm power sorts battery. Unit AZX7A. View attachment 248124View attachment 248125
Ok, so I can see it is a 6 Ah battery. Does it have a CCA rating? And have you removed all starter motor related wiring, starter solenoid etc? If that battery is healthy, there is no way a 3 ohm coil can pull it down to 6-7 volts in less than half an hour to an hour.
 

Rook32432

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Ok, so I take it that this is a 7Ah battery? Does it have a CCA rating? And have you removed all starter motor related wiring, starter solenoid etc?
The sticker on top says 6ah. When I was using the starter it would crank quickly and solidly so I would think above 200CCA, unfortunately there isn’t anything specifying on the box or battery itself. A googoo search may be in order. Yes I have removed the starter wiring as I have grown to enjoy the kick much more, despite the human starter having its own fair share of wiring issues.
 

Jan_P

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OK I am a bit busy right now
I dont exactly know whats inside a coil like that someone else chime in

Now for experimental progress . If you have both points connected and battery goes down
Either it is the supply --Weak battery or consumer A partial short somewhere

I would probably disconnect the Left and Right points both and then connect only the right and observe if the Voltage drops

or something else both connected and disconnect left
If it drops so I would at this point in time assume a partial short in the circuit for that Right Point

Maybe disconnect the condenser also

Put it like this if the left point is disconnected and the Condenser And you get a voltage drop via the right point connected / disconnected
There is only one wire ..and something to work on



1690656103596.png
 

arcticXS

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One thing to check: resistance from coil primary winding to ground (mounting points) should be very high, if not infinite (open circuit) It does not matter whether you measure from + or - terminal
 

Rook32432

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OK I am a bit busy right now
I dont exactly know whats inside a coil like that someone else chime in

Now for experimental progress . If you have both points connected and battery goes down
Either it is the supply --Weak battery or consumer A partial short somewhere

I would probably disconnect the Left and Right points both and then connect only the right and observe if the Voltage drops

or something else both connected and disconnect left
If it drops so I would at this point in time assume a partial short in the circuit for that Right Point

Maybe disconnect the condenser also

Put it like this if the left point is disconnected and the Condenser And you get a voltage drop via the right point connected / disconnected
There is only one wire ..and something to work on



View attachment 248162
One thing to check: resistance from coil primary winding to ground (mounting points) should be very high, if not infinite (open circuit) It does not matter whether you measure from + or - terminal
So I have got the bike back home.
I have stripped the janky wiring down to just ignition system and charging system.
A few things I found:
Testing resistance on the coil primary to the mounting points. I didn’t know if you meant the core (mounts of the coil) or the mounting points of the engine/frame. So I did both.
With my meter set to 200ohms, the reading from either side of the coil primary to the coil mounts(core) is infinite. From the (+) side of the coil to the engine is 3ohms and .5 ohms on the (-) side of the coil to the engine.

Also, when I disconnect the ignition system, spark plug wires and all -just the charging system wired, with the key on the voltage drops to 6v.

So I am beginning to think, while I am having a voltage drop through the points wire, I am also, with the ignition completely disconnected, getting the same voltage drop with just the charging system connected.

I have yet to pull the left side cover away to dig, poke and prod, but I believe my charging system may be shorting to the engine/frame and thus, when I connect the ignition system and give power to the points it is somehow drawing power from the battery as well. Again, I am an idiot so any input is greatly, monumentally appreciated.
 
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