Alternator Wiring Question

I'm new to the sight and having trouble wiring my charging circuits. I bought a 80 KZ1000 LTD, that had a melted wiring harness. I'm building a bobber out of it, so it was no big deal. I've got all the wiring worked out, thanks to this forum, all accepted for the charging system. I've found good descriptions of the wiring I have but not clear were they're to be wired. I've got 3 yellow wires (alternator outputs) going to the regulator/rectifier. One white w/red stripe wire going to battery. One black w/yellow wire from the regulator/rectifier (part of ground circuits) is this suppose to to ground? Next is the brown wire, from the regulator/rectifier (the voltage sense wire) were is this suppose to go? Thanks in advance for any help.

The regulator/rectifier plug on the 80’s bikes usually has six wires in it:

A. One (1)WHITE with RED stripe, this is the bikes main power wire usually 12 gauge in size.

B. One(1) smaller Brown wire, probably 18 gauge or so, the voltage sense wire for the regulator/rectifier, helps keeping it from overcharging the battery.connect it to a steady 12 volt source(like the running or tail light circuit).

C. One(1) BLACK with YELLOW stripe wire, part of the ground circuits, maybe 16 gauge in size.

D. Three(3) YELLOW wires, maybe 14 gauge in size, the alternator output wires going to the regulator/rectifier which converts the Alternating Current(A.C.) to Direct Current(D.C.) using rectification, producing the power to run the motorcycle and charge the battery.

Does this help?

Yes, thanks again.

MFolks wrote: The regulator/rectifier plug on the 80’s bikes usually has six wires in it:

A. One (1)WHITE with RED stripe, this is the bikes main power wire usually 12 gauge in size.

B. One(1) smaller Brown wire, probably 18 gauge or so, the voltage sense wire for the regulator/rectifier, helps keeping it from overcharging the battery.connect it to a steady 12 volt source(like the running or tail light circuit).

C. One(1) BLACK with YELLOW stripe wire, part of the ground circuits, maybe 16 gauge in size.

D. Three(3) YELLOW wires, maybe 14 gauge in size, the alternator output wires going to the regulator/rectifier which converts the Alternating Current(A.C.) to Direct Current(D.C.) using rectification, producing the power to run the motorcycle and charge the battery.

Does this help?

I'm going out on a limb here for a moment. While connecting the brown voltage sense wire to the tail light circuit will work normally, what would happen if the fuse blew in that circuit? Would the sense wire read 0 voltage and increase output to the battery and possibly fry it? Just thinking out loud here. I would think about connecting the sense wire to the hot coil terminal. If you lose power there the bike is dead anyway, no over voltage problem.

Good idea, if it not running it can't fry anything. Thanks.

TomW wrote: I'm going out on a limb here for a moment. While connecting the brown voltage sense wire to the tail light circuit will work normally, what would happen if the fuse blew in that circuit? Would the sense wire read 0 voltage and increase output to the battery and possibly fry it?

YES

TomW wrote: Just thinking out loud here. I would think about connecting the sense wire to the hot coil terminal. If you lose power there the bike is dead anyway, no over voltage problem.

That's a better choice, but if the kill switch is used to turn off the ignition while the bike is coasting in gear, the same thing will happen... overvoltage.

Normally it's tapped into a switched 12v source on the same fuse as the ignition. If it's on the ignition wire from the key switch, it's tapped before the kill switch. Sometimes the brown wire just has it's own tap from the key switch. The most direct route prevents voltage sag in the circuitry from affecting the output voltage on the regulator. If there were a faulty connection on the ignition wiring, the voltage would sag every time the ignition coils take current. This would lead to an overvoltage pulseing on the regulator output.

loudhvx wrote:

TomW wrote: I'm going out on a limb here for a moment. While connecting the brown voltage sense wire to the tail light circuit will work normally, what would happen if the fuse blew in that circuit? Would the sense wire read 0 voltage and increase output to the battery and possibly fry it?

YES

TomW wrote: Just thinking out loud here. I would think about connecting the sense wire to the hot coil terminal. If you lose power there the bike is dead anyway, no over voltage problem.

That's a better choice, but if the kill switch is used to turn off the ignition while the bike is coasting in gear, the same thing will happen... overvoltage.

Correct but it wont be for long. :lol:

[/quote]Normally it's tapped into a switched 12v source on the same fuse as the ignition. If it's on the ignition wire from the key switch, it's tapped before the kill switch. Sometimes the brown wire just has it's own tap from the key switch. The most direct route prevents voltage sag in the circuitry from affecting the output voltage on the regulator. If there were a faulty connection on the ignition wiring, the voltage would sag every time the ignition coils take current. This would lead to an overvoltage pulseing on the regulator output.[/quote]

Agreed.

Thanks for the help, working well @ 13.4 volts.