Hey Y'all
I have a wicked short in my 85 sportster ironhead. Put a new s&s carb on last week and somehow created a short. when battery is hooked up red lead wire from battery to copper terminal gets smoking hot. Other end of copper terminal (to coil) is not. Does the copper terminal short out? and Do they occasionally need to be replaced? Can not find the short any where else. Checked every wire to every accessory and and my only clue id a very hot lead wire. any help is greatly appreciated. went this whole week without riding. Thanks

 

[/font]chaz......Can you explain what it is that you refer to as 'the copper terminal?'
I assume the bike ran fine before you put the carb on. You seem to think you have somehow created a short when you did the install.
I happen to agree, but it could be something that just happened at an odd time.
In that wire, starting at the battery and following it to it's termination point, there is definitly a short somewhere. Copper conducts electricity very well. That is why it is used. No, copper does not need to be replaced. Your problem is this:
The battery '-' ground wire is connected to the frame. The '+' side of the battery connects to an item (such as the starter, ignition switch and a number of other items) that are insulated. Somehow one of these wire(s) has touched bare steel of the frame, or you have inadvertently connected a grounded wire to this circuit.
You are just going to have to find damaged insulation. Try running a temporary wire from the battery post to the termination end of the existing wire. Disconnect the factory wire that is now shorting.
If this results in no short, as it should, then that is more proof and you have to find where that spot is in the wire that went bad.

 

thanks for the help piniongear. Greatly appreciated. The copper terminals are the small blocks on the rear wheel well, under the seat, the the wiring goes through, Kind of like a fuse box. However, i am tracking down my problem and hope you have some advise. I traced the short by trial and error as i couldnt find anu frayed insulation. When i disconnect the connecting plug, under the engine, that connects two wires from the altinator to the voltage regulator ,mounted on the front of the bike frame, the short dissappears. Can the alternator or the voltage regulator go bad and create a short? I cant see any frayed wiring. Can they be tested with a multimeter? Thanks

 

Hey chaz........Yes the voltage regulator can go bad, as can the alternator. However, I do not know if this could result in a short. The only way I know of testing the regulator is with an instrument that is know as a Vat 26 Tester, but that is used on a generator system, not an alternator.
Do you have a factory service manual? If you do, then the procedure will be outlined for you as to how this is done. When it comes to alternator system, I am in a little over my head, as I am accustomed to generator systems on the older bikes.

I have to go back to the fact that your bike ran fine until you installed the carb. That has nothing to do with electrical of course, but it would be unusual for something to decide to short out at that same time. Did you do anything or disconnect any wiring when you did the carb? I wish I had a manual on an 85 Sportster, but the latest one I have is 1974 and that is not an alternator equipped model.
Substituting the voltage regulator with a new one is an expensive test. Can someone weigh in here and give a hand as too what the problem may be? I will keep looking for some answers chaz..........piniongear

Edit note: chaz....that copper connection that you are connecting the battery + wire to: Have you checked to see if the copper is grounded to the frame? I am not familar with this connector, but I assume it is there to connect two (or more) positive wires together. If that is the case, then it should be insulated from the ground circuit. Try putting a lead on it (the copper)using an ohm meter and putting the other lead on a good unpainted piece of metal (bolted to the frame) This should show no continuity. If the meter shows continuity, then there is your short (the actual short may be on the other wire(s) attached to the copper terminal somewhere down the line. Just a thought I had regarding the problem.