Red Wire Bypass

mattgarr57

mattgarr57

Joined
Oct 7, 2017
Messages
86
Location
Richmond, VA
Bike
2002 ST1100
Sorry, I know this has likely been discussed many times, but is it smart PM to do the red wire bypass? 2002 ST1100
 
At the very least you should take a look and the connector involved and check for corrosion of the contacts and any heat damage to its plastic. Given the problem with some older GoldWing corrosion is alternator capacity agnostic.
 
Oldbikefixr said:
I thought that was applicable to the 1991-1996 bikes with the 28 amp alternator.
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The bypass applicable to 1991-1995 STs that have the 28 ampere alternator is, I think, for their red connector that connects their 3 yellow wires carrying the AC alternator output.

The red wire bypass mentioned above seems to be instead dealing with a red wire for the starter solenoid. [This comment has been edited in order to correct it.]

Any and all,

Can you provide a link to the article on this site that discusses the red wire bypass? (Oops, I did not see that ST11Nut already did that above.)
 
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DaveWooster said:
[...]

The red wire bypass mentioned above seems to be instead dealing with a red wire for the starter solenoid, which probably carries the strong, DC current needed to operate the starter motor.

[...]
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That little red wire coming from the solenoid that people bypass definitely does not carry the current to operate the starter motor.
 
jrp said:
That little red wire coming from the solenoid that people bypass definitely does not carry the current to operate the starter motor.
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Ok, I edited out that part of the comment in my post above.
The quoted statement has been shortened to read "The red wire bypass mentioned above seems to be instead dealing with a red wire for the starter solenoid."
 
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Oldbikefixr said:
Thought that was [only] applicable to the 1991-1996 bikes with the 28 amp alternator.
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No, for sure, it applies to all ST 1100s. The red wire burned up on my 2001 ST 1100 - which forced me to carry out the bypass at the side of the road in Belgium - see picture below.

Michael

Burned-up Red Wire - 2001 ST 1100
243329
 
I'm looking toward re-routing the headlight power to its own direct feed from the battery, which will relieve the ignition switch and wiring of what is probably more than half of their load. It's controlled by relays, so there's no reason for it to run through the ignition.

However, the headlight relay wiring is also on that fuse, so it will need to be re-fed as well. I intend to feed it from the switched side of the kill switch, so the headlights will be off when the engine is off, a feature I included when I added headlight relays to my Nighthawk.

I could also add an ignition-coil feed and relay, which should result in a slightly hotter spark, while likewise relieving that wiring of the load. I've also looked at the cooling fan wiring, but taking that off the ignition switch means it could run after turning off the bike.
 
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Larry Fine said:
I'm looking toward re-routing the headlight power to its own direct feed from the battery, which will relieve the ignition switch and wiring of what is probably more than half of their load. It's controlled by relays, so there's no reason for it to run through the ignition.
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A recent charging system thread seemed to come to the conclusion that the alternator senses the voltage downstream of the ignition switch and tries to regulate that within a particular voltage range. As more load is put on the system, the voltage drop across the ignition switch increases (V=I*R), so the alternator is obligated to put out more current and raise the voltage at the battery terminals to keep the sensed voltage in the desired range. If you remove the headlight current load from the ignition switch path it will decrease the voltage drop across the ignition switch and the alternator will put out less voltage/current because the sensed voltage will be higher than typical for the actual current load on the battery. Not sure if this will cause the battery to drain faster or not, but its a possibility that should be considered.
 
dwalby said:
Not sure if this will cause the battery to drain faster or not, but its a possibility that should be considered.
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"Captain Kirk, I shall consider it!"

If I can locate that particular tap, I cab always relocate it to an appropriate point.
 
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For the ABS versions of the ST1100, the headlamps are not powered through the ignition switch. It does not cause the battery to drain faster.

dwalby said:
A recent charging system thread seemed to come to the conclusion that the alternator senses the voltage downstream of the ignition switch and tries to regulate that within a particular voltage range. As more load is put on the system, the voltage drop across the ignition switch increases (V=I*R), so the alternator is obligated to put out more current and raise the voltage at the battery terminals to keep the sensed voltage in the desired range. If you remove the headlight current load from the ignition switch path it will decrease the voltage drop across the ignition switch and the alternator will put out less voltage/current because the sensed voltage will be higher than typical for the actual current load on the battery. Not sure if this will cause the battery to drain faster or not, but its a possibility that should be considered.
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jrp said:
For the ABS versions of the ST1100, the headlamps are not powered through the ignition switch. It does not cause the battery to drain faster.
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Is the ABS system powered through the ignition switch? If so, and if it consumes similar power, that would help keep the alternator output fairly high.

Since the non-ABS ST1100s also have high/low beam headlight relays, it would have been simple enough to power them independently of the ignition switch like with the ABS models, but Honda chose not to. Its anybody's guess why that is, but one reason could be alternator output control.
 
On my '98 ABS, no, the ABS is not powered through the ignition switch. There is a separate ABS fusebox that is directly connected to the battery.

It would be interesting to know how many of the red wire failures happened on non-ABS ST1100s versus ABS-equipped bikes. Not sure that would prove anything though; I assume many more non-ABS bikes were made than the ABS ones.

As you, I also wonder why Honda chose the route they did with the non-ABS models with regards to using headlight relays but powering them through the switch anyway. You may be onto something with the way the charging system works, but I don't know enough about the ST1100 charging system to comment on it.

dwalby said:
Is the ABS system powered through the ignition switch? If so, and if it consumes similar power, that would help keep the alternator output fairly high.

Since the non-ABS ST1100s also have high/low beam headlight relays, it would have been simple enough to power them independently of the ignition switch like with the ABS models, but Honda chose not to. Its anybody's guess why that is, but one reason could be alternator output control.
Click to expand...
 
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jrp said:
On my '98 ABS, no, the ABS is not powered through the ignition switch. There is a separate ABS fusebox that is directly connected to the battery.
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From what I see on the wiring diagram, there is a single 10A fuse for the ABS system that is controlled by the ignition switch. That circuit energizes the relays for the other two 30A fused ABS circuits that are hardwired to the battery, and also drives a couple other ABS related functions. So there is an additional load through the ignition switch for the ABS system, not necessarily equivalent to the two headlights, but significant enough to warrant its own 10A fuse.
 
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