Old Bike, new problem.

So I had this same problem, did the suggested repairs but more wires and connectors kept melting. Finally it was fried and wouldn't run any longer. I've purchased a new/used wiring harness with really good connectors. I'm about to disassemble as much of the bike as I need to, if it doesn't work then I'm parting it out.

What I can't seem to find in a search is the 40 amp conversion that I know I've read about in the past. Can anyone guide me in that direction? And does anyone facing these wiring meltdowns have any other diagnosis? I'm gonna be pissed if I take it all apart and it runs but then continues down the same path...

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Folks:

Where is this connector found on the ST 1100? The picture below is an enlargement of the same picture that was posted on page 1 of this discussion.

Michael

Where & what is this connector?
image-jpg.165418
 
John OoSTerhuis said:
Then I'd do the main fuse bypass mod: remove the red lead from the melted main-fuse/starter-relay 4P and connect it directly to the battery's positive post through a heavy duty inline fuse holder with 30A fuse [see the AOW for the 'how to' article].
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Looking at the wiring diagram in my Clymer book, I see that, despite being relay controlled, the headlights are powered through the ignition switch (why?), and is the only circuit using a 20a fuse.

Wouldn't re-routing the headlight circuit to be fed directly from the battery eliminate around half of the current carried by the ignition switch and possibly eliminate the connector melting issue?
 
Larry Fine said:
Looking at the wiring diagram in my Clymer book, I see that, despite being relay controlled, the headlights are powered through the ignition switch (why?), and is the only circuit using a 20a fuse.

Wouldn't re-routing the headlight circuit to be fed directly from the battery eliminate around half of the current carried by the ignition switch and possibly eliminate the connector melting issue?
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Yes, and it would also reduce the voltage drop across the ignition switch, but c'mon Larry, repeat after me "Honda designed it that way for a reason". Back in the early 2000's I went to Japan on business, and before going there we were given training on Japanese culture, which explains a lot of these kinds of mysteries, but I won't bother getting into it here.
 
I can't tell if you do or don't know why. ;) In case a relay faults closed? One in a million.

It almost defeats the advantage of using relays. I always run mine direct from the battery.

I think that's the route I'll take when the time comes (unless it's already been addressed.)
 
Larry Fine said:
I can't tell if you do or don't know why. ;) In case a relay faults closed? One in a million.

It almost defeats the advantage of using relays. I always run mine direct from the battery.
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No, I don't know why. The starter relay has a direct hot connection to the battery, so I don't know why a headlight relay couldn't also have a direct hot connection to the battery as well. But I don't design automotive electrical systems, so I'm not claiming to be an expert either.

edit: I think I know why, the voltage drop across the ignition switch is used by the alternator to determine the electrical load on the system. If the headlights were removed from that circuit, one of the highest loads wouldn't be in the path that's being monitored. I've never seen any other system that didn't have the headlight load on the main ignition switch path, so I think that's the reason why they do it that way.
 
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Doug: I seriously doubt that. The ignition switch doesn't have a know resistance so their can't be a known relationship between the voltage drop and current.
 
Jim Van said:
Doug: I seriously doubt that. The ignition switch doesn't have a know resistance so their can't be a known relationship between the voltage drop and current.
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I had a Yamaha years ago with corrosion in the connector between the battery and ignition switch. Alternator was charging battery to 15.1v. Removed 0.7v drop from that connector and alternator went to 14.4v. Ignored Yamaha mechanic analysis that it was a bad voltage regulator and I should replace it to solve the problem. There's no theory of operation documentation for m/c alternators, but with a little analysis and careful voltage measurements I was able to figure it out. The charging system monitors the voltage downstream of the ignition switch and attempts to adjust it to a specific level. The more load being supplied by the battery, the more drop across the ignition switch, the lower the downstream voltage that the charging system sees, and it responds by charging the battery with the required voltage to counteract the drop.
 
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Sure: It all depends on where the voltage is "sensed" by the voltage regulator. It would be better ( to a degree ) to sense the voltage at some "disatnce" from the battery. to help offset the normal drop in voltage along a wire, as far as the "loads" are concerned. But there is a down-side.

Sounds like a good idea, but sometimes I wonder if this can be a bad idea. For instance, if the headlamps and tail lights are getting the full charging voltage, they may be a little brighter, but the bulb life is shortened significantly. I believe the lamp life is proportional to the 13th power of the voltage applied. So if the voltage is increased by 5%, Bulb life is shortened by about 50%.

I think a "12 volt" bulb is designed to run at about 14 volts, not 12 volts, BTW. 12 volts is the nominal voltage.

EDIT : Opps, make that the 16th power : http://www.newworldencyclopedia.org..._bulb#Voltage.2C_light_output.2C_and_lifetime
 
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