Relay bypass alternative ideas

[Larry Fine]

Decided to start its own thread:

I haven't looked at my actual bike's innards yet, but I have scoured the wiring diagrams and photos, and want to do something kinda similar to lessen the ignition switch's load. I would appreciate the opinions of the wiring guys.

My intention is to re-feed the headlight fuse, which appears to have its own separate supply wire to the fuse block, directly from the battery via a new fusible link. The headlights use relays, so why switch the power? Now, doing this also means the wire feeding the headlight-interrupt contacts in the starter button will be hot.

However, I also intend to disconnect that and instead feed the headlight-interrupting contacts from the switched side of the engine-kill switch, so the headlight won't be on when sitting with the engine off, but I want power on. The running-, tail-, and gauge lights will still be on, but the battery drain will be much lower.

I'm also thinking of adding an ignition-coil supply and relay, so the bike's wiring only carries relay-coil current, possibly allowing for a hotter spark. The power wire could share the new fusible link and wire that I mentioned above, figuring that a 30a link and 10-gauge wire should be plenty heavy enough for everything.

The reason I'm looking at the headlight circuit first is that it's the only 20a fuse, and I haven't swapped them for LEDs yet. When I do, I could even lower the fuse rating, but figure the direct supply will still allow for a slightly greater voltage at the lights, same as the ignition relay idea. So, what do you guys think?

 

[jrp]

If it were me, I would just do the ignition relay bypass mod and be done with it. It will take enough load off your red wire so that it won't ever melt the connector on the starter relay.

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.

Decided to start its own thread:

I haven't looked at my actual bike's innards yet, but I have scoured the wiring diagrams and photos, and want to do something kinda similar to lessen the ignition switch's load. I would appreciate the opinions of the wiring guys.

My intention is to re-feed the headlight fuse, which appears to have its own separate supply wire to the fuse block, directly from the battery via a new fusible link. The headlights use relays, so why switch the power? Now, doing this also means the wire feeding the headlight-interrupt contacts in the starter button will be hot.

However, I also intend to disconnect that and instead feed the headlight-interrupting contacts from the switched side of the engine-kill switch, so the headlight won't be on when sitting with the engine off, but I want power on. The running-, tail-, and gauge lights will still be on, but the battery drain will be much lower.

I'm also thinking of adding an ignition-coil supply and relay, so the bike's wiring only carries relay-coil current, possibly allowing for a hotter spark. The power wire could share the new fusible link and wire that I mentioned above, figuring that a 30a link and 10-gauge wire should be plenty heavy enough for everything.

The reason I'm looking at the headlight circuit first is that it's the only 20a fuse, and I haven't swapped them for LEDs yet. When I do, I could even lower the fuse rating, but figure the direct supply will still allow for a slightly greater voltage at the lights, same as the ignition relay idea. So, what do you guys think?

 

[Shawn K]

Wouldn't it be easier to just put a heavy-duty weatherproof on/off switch on the headlights? I did that with my old CB900C so that I could idle the bike indefinitely (read: winter warm-up) without there being a net drain on that bike's weak charging system. I had a Windjammer fairing on that bike, and I mounted the switch in the fairing. Worked a treat.

 

[Bush]

I'm also thinking of adding an ignition-coil supply and relay, so the bike's wiring only carries relay-coil current, possibly allowing for a hotter spark.

Seems to me a spark is a spark. Over thinking this whole thing just a bit maybe?

 

[Jim Van]

I installed two sets of LED aux spotlights, one set for the slab and the other set is optionally on as an additional "high beam". I have two miniature switches ( one is a three position switch ) and a few diodes added to give me some choices. I can run only the smaller LED spots on the slab ( to save the low beam filaments ) and have only the high beam on or the higher lumen spots on plus the high beam.

The relays and diodes control the OEM low & high beam relays plus some additional relays for the spots. I also did the red wire bypass and added a 45 amp relay to take the load off the ignition switch. That should also provide a little more voltage for the coils ( much less voltage drop now between the battery and fuse block ) which will provide a hotter spark.

So, there are other options by using miniature switches and diodes to control the OEM and spot relays ( coil current, not the load currents).

This year I also added Evitek LED lamps ( on Uncle Phil's recommendation - sometimes it's worth listening to these old guys ) to replace the OEM lamps.

I can also report that my Chinese alternator is still working fine.

 

[jrp]

Seems to me a spark is a spark. Over thinking this whole thing just a bit maybe?

No, he is not. A stronger spark will give you more power than a weaker spark.

 

[jfheath]

Hmm.

Before you do that, take a look at this.

Article [13] - ST1300 - Headlight Circuit | ST1300 Articles

A Circuit Diagram showing the odd configuration of the ST1300 headlights, with some explanation. The circuit is taken from a UK 2009 ABS model - from 2004 headlamps are on all of the time, there is no light switch on the handlebar console. However, the UK spec models have a 'pass' switch to...

www.st-owners.com

Note that there are two routes for the headlight wiring. Also note that when the pass button is pressed, all 4 filaments are lit. What's that ? About 240 watts. The existing system uses power from 3 fuses.

Other thoughts.

The electrics are well designed and use components and wire which are up to the job of carrying the current required. The ignition switch is a heavy duty device.

There is limited capacity on the existing wiring for adding additional accessories without providing additional fused feeds to the battery and corresponding earth feeds. Relays with triggers from (say) the quartet harness connector should be used.

If there is a problem with load on a particular component, then maybe there is another reason for it - possibly accessories, possibly poor earths. Possibly failure to provide a separate earth for added components.

If there is an issue with poor quality spark, then consider the earthing points of the HT ignition coils. Remove the bolts, lift away the coils and clean up the bolts and metal strips. Also check for corrosion i side the copper cored HT leads.

Although the red wire bypass seems to be a common solution, that relay does not get hot just by itself. It needs some help. Too much load, corroded terminals, poor earths ?

I've only ever had one fail on me. it was on my first 1100. The cause was corroded terminals in the connector housing, and the corrosion had spread into the cables in the loom. The terminals overheated with the extra load and melted the housing.

 

[GGely]

I’m in the “do the bypass and call it a day” camp. You’re considering a bunch of work for not a lot of return. Bypass and LED bulbs and never touch it again.

The best part of using LED’s (other than performance) is that you can replace the main fuses with smaller 40amp ATO’s for a much neater installation.

 

[rwthomas1]

I went round and round with this and came to the conclusion that I'm not messing with the wiring harness as Honda designed it. What I am doing to checking the connections, putting a bit of dielectric grease on them and leaving it be. I'm also shedding the headlight load, even though now its just LED, to a relay and dedicated wire. Doing the same for the horn, as that is getting upgraded. Once done, the red wire (provided its in good shape) shouldn't have any problems.

RT

 

[kiltman]

If you don't want to do the "Red Wire bypass" consider making one of these up and put it in your fairing pocket. If you're away from home and the red wire fails you simply patch into the red wire further up with the posi-tap and connect to the main relay. This will get you home, and then you can resolve the issue with a permanent solution.
One doesn't really need any tools to do the repair