Why?

[MrYeats]

Why are my new coils starting to get hot?
I put coils on to match the points now, and I get 12v to the lead wire, I get 12v to the points but points don't fire and the coils start to heat up AGAIN!
I am at my wits end and have spent hundreds of dollars to get timing and carbs all fixed and ready to go.
I can't take it any more. I believe I will part it out and forget it.

 

[drewpy]

Coils get hot because the primary is not energising the secondary via the points

Are your points earthing to ground?

you sure they have been installed correctly?

need to ensure that the insulators are working as they should and also a condensor fault can create a short in this situation

 

[MrYeats]

Is it important that the negative lead go to ground from the coil?
The coils have a black lead and a yellow lead but no markings as to which is positive or negative.

 

[bcware]

Do you have your original coils? The aftermarket replacements should look very similar to the originals. Ignoring color, if you hold them side by side in the same orientation the wires will emerge from the same place on the coil. Ignore the color; hook them up based on where the wires are coming from.

 

[xschris]

With points you need to have 4 ohm coils. The later bikes used 3ohm.

 

[MrYeats]

The coils I have are 3ohm and the color wire that is red and white on the original is black on these and where the colors on the original that were gray or orange, are yellow on this set.

 

[MrYeats]

Here is a summary of how the wiring goes...
From the on/off or kill switch, the hot 12v lead goes to bothe black leads on the coils.
Then the condenser is wired to the yellow lead on each coil and splits off to the points, left to left and right to right.
When the voltage is checked I get 12v all the way to the base plate on the points if one is closed.
Soon the coils start to get heated and the voltage stops at the black lead on the coils, not going all the way to condenser or points.

 

[drewpy]

Here is a summary of how the wiring goes...
From the on/off or kill switch, the hot 12v lead goes to bothe black leads on the coils.
Then the condenser is wired to the yellow lead on each coil and splits off to the points, left to left and right to right.
When the voltage is checked I get 12v all the way to the base plate on the points if one is closed.
Soon the coils start to get heated and the voltage stops at the black lead on the coils, not going all the way to condenser or points.

is it the proper condensor ie 2 condensors in 1 and are they earthed?

so if points are open, nothing gets through there?

think of the ignition as two completely different circuits sharing a common 12v supply

if the engine is not running the coils will heat and fail due to the primary coil acting like a 1 bar heater.

when the engine is running, they will be warm to touch

hope that helps