It was an issue on the 28 amp units as well. I had it go on my 1990 model,(28amp) and my 97(40amp)
Red Wire Bypass or Ignition Relay Bypass
- Thread starter rwthomas1
- Start date
Thank you for pulling all of that together. Those diagrams are from the Honda manual, and cover through the '95 models, so I'm guessing that fuse block is, too; the '96-on are different. I happened across a wiring harness in Canada for those years in case anyone is looking:
OEM Main Wire Harness Silicion CDI Fusebox Regulator Loom 1990 Honda ST1100 | eBay
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Definitely will. I believe my Clymer also shows the same separate wire, but it stays on the bike (since it's smaller and lighter than the Honda manual is) so I'll have to look at it later.
I came across a previous thread that I had started about my questions, and forgot about it. In it, JRP responded (thanx!) that there are indeed discrete wires feeding the headlight fuse (and the fan fuse), so my idea should be easy to implement.
I would plan on re-feeding Wire 1 primarily, and will consider Wire 3, allowing the coolant fan to run after parking. I still wonder why they ran the headlight power through the ignition switch.
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It is run through the ignition switch because in addition to feeding the line side of the headlight relays, the circuit provides the headlight relays with coil power after passing through the NC contacts in the starter pushbutton switch. This is what operates the headlight cutout function when the starter switch is pressed. You have to re-power the relay coil circuit from a switched fuse or the relays will function with the key off.
Semantics, perhaps, but I see it as the opposite: They went ahead and fed the relay control from the same fuse because it was switched. Some other ST models do feed the headlight fuse(s) always hot.
I know, and we've already discussed it; part of my mod will be to feed the wire to the starter-interrupt from the load side of the engine kill switch, so it will also cut the headlights off when the engine is.
You don't need a 70 amp relay. A 40 amp relay will suffice. I used this one:
Motorcycle Relays, Panasonic, Mitsuba
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The Red Wire Bypass is a band-aid, and not a very good one at that. You are just trading one crimp for another (actually, you are trading one crimp for THREE crimps!) and it doesn't fix the problem. It may work long enough or not, so you are not giving yourself any peace of mind. A number of people have had a meltdown despite doing the Red Wire Bypass.
Here is a different way to do the fuse box part of the Ignition Relay Bypass Mod without cutting any wires:
Ignition Relay Bypass Mod - ST1100 ABS | ST1100 Related
I'm am planning a long trip next year that will find me in the boonies from time to time, so I figured it was time to address the red wire issue that plagues the ST1100. It appears there are two approaches; the "red wire bypass" and the "ignition relay bypass". The "red wire bypass" really...
On your bike there are four wires going into the fuse box that are switched.
Wire 1: Headlight (20A, Red/Black)
Wire 2: Neutral, Oil, Temp, Tacho, Horn (10A, also Red/Black)
Wire 2: Position, Meter Light, Tail (10A)
Wire 2: Ignition, Starter, Alternator (10A)
Wire 2: Turn Signal, Brake (10A)
Wire 3: Fan Motor (10A, Blue/Orange)
Wire 4: Accessory (5A)
If you just bypass wires 1 and 2, then the only things that will be left on the red wire are the fan motor and the clock. If you are using the accessory terminal to power something, then add five amps max, but still no problem.
If you take your time and do all your own crimps, then failure points shouldn't be a worry. Remember, you are eliminating failure points by doing the mod.
Jeff
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Jeff, thank you again for sharing that info back then and now, and for confirming my observations about there being a separate headlight-fuse wire as shown in the Honda diagram. I just checked my Clymer. Interestingly, it shows the ignition/starter/alternator fuse as the one separately fed, but I trust Honda and your observations better.
My reason for wanting to do the headlight-fuse direct feed modification is as much about providing a more direct electrical pathway for the headlights as it is about reducing current on the key switch and the main red wire. I added headlight relays to my NH750 a while back, and fed what became the control wiring from the kill switch, too.
As on the Nighthawk, I intend to use a fusible link instead of a fuse for the new supply line. They exhibit less voltage drop and have fewer electrical connection points compared to fuses. Anything else I add, such as an ignition-coil relay or auxiliary lighting, will also be powered through the new line (or two, if I go overboard with add-ons).
I'm also interested in opinions on supplying the radiator fan to stay on until the coolant cools below the temperature switch's setting. This would reduce what is called heat soak, and the coolant should circulate until the engine thermostat closes, just faster. Or, would it run long enough to become detrimental to the battery charge?
My reason for wanting to do the headlight-fuse direct feed modification is as much about providing a more direct electrical pathway for the headlights as it is about reducing current on the key switch and the main red wire. I added headlight relays to my NH750 a while back, and fed what became the control wiring from the kill switch, too.
As on the Nighthawk, I intend to use a fusible link instead of a fuse for the new supply line. They exhibit less voltage drop and have fewer electrical connection points compared to fuses. Anything else I add, such as an ignition-coil relay or auxiliary lighting, will also be powered through the new line (or two, if I go overboard with add-ons).
I'm also interested in opinions on supplying the radiator fan to stay on until the coolant cools below the temperature switch's setting. This would reduce what is called heat soak, and the coolant should circulate until the engine thermostat closes, just faster. Or, would it run long enough to become detrimental to the battery charge?
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Just interested to know, are these sold over there. Over there being you left siders 
.
Hope the link works, fingers crossed, press reply.
Upt'North.
.Hope the link works, fingers crossed, press reply.
Upt'North.
Honda ST1100 Starter Solenoid /relay Plug & Red Wire Bypass Kit. | eBay
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ST Gui
240Robert
I know the 1100's battery is a bit more studly than the 1300's but I wonder if thos won't kill the battery each time especially in hot ambient temps or at least making the subsequent start a Press and Pray drill. And given the bulletproofness of the STs — is this trip necessary? What's gained — longer oil/coolant change intervals?
You can crash 'em; you can get bored and sell 'em; you can get too old and weak to hoist it off the sidestand; but has anyone actually worn out an ST? @W0QNX is trying awfully hard, and @Uncle Phil would have a shot at it if he wasn't splitting the miles amongst four of them, but it seems that the ST's longevity is greater than the rider already. Making it last longer does what???
Opinions noted. 
I do carry a compact jump starter, but I'd certainly prefer to not need it.
I do carry a compact jump starter, but I'd certainly prefer to not need it.
rwthomas1
Site Supporter
This has been a most interesting thread. I'm not sure I buy the "red wire bypass" as not worth it. It eliminates at least 1 crimp as well as moving/isolating the main chassis power supply wire away from the starter solenoid. Upon reflection, modifying the factory harness may not be the best idea. Shedding the heaviest loads would seem more prudent.
I understand the relay on top of relay argument but would it not be simple to run a nice, fat power wire to the front of the machine, and use the headlight and horn wiring to trigger relays to handle those loads? Simple AUX fuse setup can handle this. Completely divorce the headlight and horn loads from the factory harness. Do the RWB mod, and install LED bulbs everywhere else. Seems like a very simple way to fix the problem.
I don't think there is a right or wrong way to do this, provided the wiring is sized appropriately and the theory is sound. Since there is no corrosion as of yet on mine, I think I'll simply relay the headlights and be done with it. This winter while the bike is apart, I'm going to separate, DeOxit, and grease every single terminal on the machine. This alone will go a long way in ensuring trouble-free wiring.
RT
I understand the relay on top of relay argument but would it not be simple to run a nice, fat power wire to the front of the machine, and use the headlight and horn wiring to trigger relays to handle those loads? Simple AUX fuse setup can handle this. Completely divorce the headlight and horn loads from the factory harness. Do the RWB mod, and install LED bulbs everywhere else. Seems like a very simple way to fix the problem.
I don't think there is a right or wrong way to do this, provided the wiring is sized appropriately and the theory is sound. Since there is no corrosion as of yet on mine, I think I'll simply relay the headlights and be done with it. This winter while the bike is apart, I'm going to separate, DeOxit, and grease every single terminal on the machine. This alone will go a long way in ensuring trouble-free wiring.
RT
Just interested to know, are these sold over there. Over there being you left siders
Hope the link works, fingers crossed, press reply.
Upt'North.
Honda ST1100 Starter Solenoid /relay Plug & Red Wire Bypass Kit. | eBay
Find many great new & used options and get the best deals for Honda ST1100 Starter Solenoid /relay Plug & Red Wire Bypass Kit. at the best online prices at eBay! Free delivery for many products!www.ebay.co.uk
See that inline fuse that comes in the kit? It has two crimps that cannot be inspected because it is sealed. Are those crimps of good quality? Impossible to tell without cutting it open. A lot of people use this type of inline fuse, some of which are cheap Chinese junk that can have a poor crimp which results in overheating and meltdown. Best bet is to do the crimps yourself; this way you know they are of good quality.
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And some of us, okay maybe just me, doesn't bother with any of the hair-splitting details about which oil is best, which moly is best, etc. and just rides the damn thing and hasn't encountered any problems in 23 years of riding the same ST1100. It will likely go another 23 years with very little maintenance if I wanted to keep it that long.
Don't forget LED's for the headlights as well. Mine is LED down to the dash lights with the exception of the high beam indicator and the low fuel lights. The LED high beam indicator was too bright and the low fuel light needs the filament resistance in order for the thermister circuit to work properly. For those who don't want to build their own headlight harness, Eastern Beaver has a number of high quality kits to re-power the headlight circuit. Chosen correctly, it is plug-n-play and completely reversible.
Eastern Beaver H4 kits
^ True Dat! ^
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ST Gui
240Robert
Zackley.beemerphile said:
Zackley x 2.dwalby said:
That's basically my plan, though I may run more than one, and it's what I did on my NH750. A single #10 on a fusible link, run with a #10 ground in a split loom following harness route, terminating in a pair of these:
They're AlumiConn devices made for "repairing" aluminum house wiring, but work great for other wiring, too. They're self-insulating, reusable, come with a grease already in the holes, and they're relatively inexpensive.
These new unswitched hot and ground wires supplied both the hot and ground for the following:
Headlight (through two relays)
Wolo BadBoy horn (through relay)
Amplifier and head-unit constant-hot
Ignition coil relay (hot only)
Eastern Beaver H4 kits
That's almost exactly what I made for the Nighthawk headlight. There was an un-needed 10" headlight "extension cord" with both a plug and a socket, so I cut it and inserted two relays and new hot and ground wires. The bike's wiring controls the relays, and the new hot and ground wires supply the headlight itself, as described in the previous post. I should have taken a picture.
That's almost exactly what I made for the Nighthawk headlight. There was an un-needed 10" headlight "extension cord" with both a plug and a socket, so I cut it and inserted two relays and new hot and ground wires. The bike's wiring controls the relays, and the new hot and ground wires supply the headlight itself, as described in the previous post. I should have taken a picture.
What John O. said. I've been using a 40 amp relay for years w/o a problem. I like the idea of taking the load off the ignition switch AND reducing the IR (voltage drop) drop along the wire to & from the ignition switch.
BTW, you don't have to be concerned about a surge/inrush current. The ignition switch doesn't handle the starter motor current - the starter solenoid does.
BTW, you don't have to be concerned about a surge/inrush current. The ignition switch doesn't handle the starter motor current - the starter solenoid does.
Smudgemo
Intermodal Man of Mystery
Update on my bypass mod experience just to raise awareness of failed or failing relays. In this past year I have had the starter relay and the relay for the ignition bypass mod I did both fail. Both were intermittent, but the starter relay kept working for a longer period of time and I always got home. I did the usual troubleshooting and determined the relay had gone bad, but I don't recall if it made any noise when I'd hit the starter button.
Then recently when I decided that it was maybe time to part ways with my '96, another electrical issue. This time, the no-start clues were headlights working normally but not any of the components associated with the bypass mod so I started troubleshooting like @Larry Fine always pushes members to do. Which is good advice. Thankfully this most recent no-start happened on a Sunday morning with nothing to do but a grocery run, so I decided it was time to take a look. I initially assumed the switched power connection was at fault somehow. Checking indicated the battery was good, all the connections had continuity, ground was good, fuses had continuity, switched power was good, voltage where I expected, relay clicked, the whole thing. Eventually I jumped the connections at the relay plug for power to the circuit and everything lit up like it should, so I checked the voltage output from the 87 terminal with the relay slightly pulled out where could get a probe on it and, yep, dead relay. Surprising because it was a quality unit made in Japan, but so was the starter relay (probably.)
Anyhow, the point being electrical issues can be tricky, and these relays both didn't just die one day, so there was some warning. Luckily I had a 4 pin relay that will work until I get a 5 pin replacement for my setup, and the bike works perfectly again. I also refreshed my memory on the design of the bypass mod and will carry another relay as a spare, but I realized a simple piece of wire as a bypass for the relay would get me home in a pinch. On the bright side, it was good practice for diagnosing electrical issues, and I figured I'd share my experience in case anyone runs into something similar. At least I confirmed all the work I did for the bypass was working properly, so that was cool.
My bike shows no signs of any issue with the red wire needing attention, but I do like the peace of mind and it was a fun project.
Then recently when I decided that it was maybe time to part ways with my '96, another electrical issue. This time, the no-start clues were headlights working normally but not any of the components associated with the bypass mod so I started troubleshooting like @Larry Fine always pushes members to do. Which is good advice. Thankfully this most recent no-start happened on a Sunday morning with nothing to do but a grocery run, so I decided it was time to take a look. I initially assumed the switched power connection was at fault somehow. Checking indicated the battery was good, all the connections had continuity, ground was good, fuses had continuity, switched power was good, voltage where I expected, relay clicked, the whole thing. Eventually I jumped the connections at the relay plug for power to the circuit and everything lit up like it should, so I checked the voltage output from the 87 terminal with the relay slightly pulled out where could get a probe on it and, yep, dead relay. Surprising because it was a quality unit made in Japan, but so was the starter relay (probably.)
Anyhow, the point being electrical issues can be tricky, and these relays both didn't just die one day, so there was some warning. Luckily I had a 4 pin relay that will work until I get a 5 pin replacement for my setup, and the bike works perfectly again. I also refreshed my memory on the design of the bypass mod and will carry another relay as a spare, but I realized a simple piece of wire as a bypass for the relay would get me home in a pinch. On the bright side, it was good practice for diagnosing electrical issues, and I figured I'd share my experience in case anyone runs into something similar. At least I confirmed all the work I did for the bypass was working properly, so that was cool.
My bike shows no signs of any issue with the red wire needing attention, but I do like the peace of mind and it was a fun project.