Harness...hmmmm Relays....hmmmm

[Guest]

I have my wiring harness down to wire right now. It's in decent shape and I don't think I need build a new one, which is what I was thinking to begin with. I soaked it in simple green and cleaned all the connections. I will be replacing some connectors for sure. Help me out....should I replace all of the bullet connectors on the harness? What else?

I would like to add some relays while I am reworking the harness. Which ones should I do? Coils, headlight, horn,......????

Help a brotha out....

[cowboyup3371]

I only replaced a couple of connectors two years ago when I first got my bike. It seemed to do okay but after this latest incident with the stator/rotor, I took another look at the harness and two looked melted/burnt. Consequently I've replaced all of them to ensure I have good connections. If your harness is telling you it's worn out, replace them. Get yourself a good ratcheting crimper and connectors from someplace like www.vintageconnections.com and you'll be set for a bit. (I've picked up most of my connectors and terminals from Cycle Recycle II).

[Dogma]

Add relays to any circuit that has a significant voltage drop due to dirty switches and connectors. Make sure to use vibration-tolerant relays. People have lost power to their coils because of vibration-induced coil failure, some carry a spare relay. Or, clean your switches and connectors and protect them with dielectric grease. With clean connections and switches, adding relays will only get you increased complexity to go with some increased tolerance for dirty components.

Some people like to replace all the bullet connectors with something else they think is better (and very well may be), but the bullet connectors work fine if they're in good shape. Clean them, protect them with dielectric grease, and make sure they're tight. Keep it stock, call it done. Measure voltage at the coils, headlight, whatever and notice the puny voltage drop from the battery.

You didn't mention it, but while you've got the harness apart, inspect the wires to make sure they're all in good shape. Especially look for chafed insulation where it may have rubbed on the frame, or heat-damaged (brittle) insulation near the head. Look for corrosion near connectors making the wire brittle too. I once lost power to a coil when an brittle wire broke off where it entered the coil. Oh, and bypass the stator leg loop that goes up to the connector under the tank, if you have one.

[Good Times]

You didn't mention it, but while you've got the harness apart, inspect the wires to make sure they're all in good shape. Especially look for chafed insulation where it may have rubbed on the frame, or heat-damaged (brittle) insulation near the head. Look for corrosion near connectors making the wire brittle too. I once lost power to a coil when an brittle wire broke off where it entered the coil. Oh, and bypass the stator leg loop that goes up to the connector under the tank, if you have one.

Good thoughts Dogma. I am going through each wire an plan on replacing any that are chafed or stiffened from heat.

[keman]

While you have the wires out, feel each wire for stiff sections. My main ground from the battery to the case "looked" fine, but flexing it with my fingers found a hard spot. After I replaced it, I cut the old wire open and found a two inch section that was essentially Copper rust dust. Not one stand of the wire was still good. ..

[keman]

There are lots of connectors in there that you really do not need. As you go through the system replacing bits, solder the ones you can. Get rid of any connectors that you will not need to pull apart later.

I even soldered a few that may need to be taken apart later "stator/RR, coils, etc..." I just made sure to leave a little extra wire for later repairs.

[Good Times]

Yeah keman, I have already found stiff wires that I am going to replace.

[Normk]

The easiest way to answer the question: "I would like to add some relays while I am reworking the harness. Which ones should I do? Coils, headlight, horn,......???? " is to do a voltage drop test on the circuit in question. A good rule of thumb is that there should be less than 0.2 volts drop in any circuit or (switching) component.

Connect your voltmeter to the fuse and to the headlight terminal in question (i.e. high beam), switch on and the voltage indicated will be the voltage drop between the fuse box and the headlight. You have measured the voltage required to force the current through the circuit being spanned.

The sum of the voltage drops in a series circuit equals the source voltage. This is an important and simple to understand principle. Taking the battery voltage with switch on as 12 volts as it's easier to type, the voltage applied to the headlight will be 12 volts minus the voltage lost in forcing the current through the main fuse, up to ignition switch, back to the fuse box, back up to the dimmer switch, to the headlight.

Also subtracted is the voltage required to force the current through the wiring from the headlight to ground and to the battery.

Place your voltmeter across the headlight's right and left terminals (with light plugged in and on) and the voltage across the headlight will be measured. Subtract this number from the voltage measured across the battery with headlight on and the difference is the lost voltage or voltage drop in the total circuit.

OK, it's all well and good to measure that the headlight is not operated by full battery voltage but how to find the locations of the losses? This is done as described, by measuring, by voltmeter, the loss in each run of wire or across each swich while operating.

If one is concerned about the condition of the wiring harness, checks such as those recommended above, to determine physical condition of the wire insulation is an important consideration. Voltage drop tests under the same load as in use will show the condition of the conductors.

There is little purpose to be served by installing additional complication where there is no benefit. An example would be the installation of a relay into a circuit which does not exhibit excessive voltage drop or line loss, if one prefers that term.

Most motorcyles have a large voltage drop in the ignition switch circuit and in many cases this is the main loss so that addressing this problem negates the need for headlight relays. On the other hand, machines such as the KLR650 Kawasaki are best served by installing headlight relays as this removes almost the total load from the ignition switch circuit.

Do the measurements, consider the data and make decisions based on the best options.

Another option is to remove the load from a circuit by using a lower draw component. LED lights may drop the load to the point where the existing wiring is more than adequate.

If someone does not understand the concept of voltage drop testing, a more complete explanation is easy enough to provide.

HIH

Norm

[Good Times]

Wow Norm. Thanks. That really clears things up for me. Seriously. Thanks for taking the time to write that up. Relays are to help with voltage drop, which I now understand and to help reduce the amount of current running through a switch that may deteriorate over time.

So if I have good wires, clean connections and clean switches, "I should be just fine" is what I'm hearing.

I am also thinking after considering this that I need to be looking at my grounds to be sure they are all good and consider how they are run.

[Normk]

The grounds can be checked in the same manner. Headlights generally ground from the left hand terminal (as viewed from rear) so use voltmeter leads between that terminal and a good ground such as an engine bolt or battery negative. Switch on and the voltage measured should be less than 1/2 volt although I look for 0.2 or less. A common problem for many bikes is a small sized common ground wire in the wiring harness. Around the early 1980's, Japanese bike makers converted from grounding components to the chassis/body near the component to the use of a common ground wire in the wiring harness. This has some advantages and disadvantages but typically they use too small a size of ground wire which results in excessive voltage drop.

I often seen over one volt drop in the headlight ground circuit which, of course, reduces headlight output. My Kawasaki KLR650, for example, had a headlight which was brighter with engine not running (about 12 volts battery voltage) than did stock ones with engine running (about 14.5 volts) because I had removed 3+ volts of loss in the ground circuit and wiring harness.

The strategy I usually employ to improve headlight output is to remove the ground terminal from the headlight plug, solder in a 14 guage wire in addition to the original common ground wire and reinstall the wire into the headight plug. The new ground wire assists in two ways:

1) It reduces voltage drop in the headlight ground circuit and so improves headlight output.

2) Removes the load of the headlight and many other loads from the common ground circuit which improves the power to other components.

Connect your voltmeter positive to the headlight ground terminal and to a good ground. Measure the voltage drop with engine running and note the headlight brightness and voltage drop. Now connect a jumper wire between the headlight ground terminal and an engine bolt.

Note that the headlight becomes brighter as the voltage drops to nearly zero?

Norm

Wow Norm. Thanks. That really clears things up for me. Seriously. Thanks for taking the time to write that up. Relays are to help with voltage drop, which I now understand and to help reduce the amount of current running through a switch that may deteriorate over time.

So if I have good wires, clean connections and clean switches, "I should be just fine" is what I'm hearing.

I am also thinking after considering this that I need to be looking at my grounds to be sure they are all good and consider how they are run.

[Good Times]

sweet. thanks norm

[Good Times]

Oh, and bypass the stator leg loop that goes up to the connector under the tank, if you have one.

I keyed in on this and looked at my harness today. Yes I believe I do have that loop. White wire with a red stripe that runs up through the harness under the tank and loops through the 9 pin connector into a white wire that has a green stripe and then back down to the stator. Is that what you are talking about?

How would I go about bypassing this loop? What's the purpose of it?

I would have to replace these wires anyway. They are fried.

[duaneage]

Add relays to any circuit that has a significant voltage drop due to dirty switches and connectors. Make sure to use vibration-tolerant relays. People have lost power to their coils because of vibration-induced coil failure, some carry a spare relay. Or, clean your switches and connectors and protect them with dielectric grease. With clean connections and switches, adding relays will only get you increased complexity to go with some increased tolerance for dirty components.

Some people like to replace all the bullet connectors with something else they think is better (and very well may be), but the bullet connectors work fine if they're in good shape. Clean them, protect them with dielectric grease, and make sure they're tight. Keep it stock, call it done. Measure voltage at the coils, headlight, whatever and notice the puny voltage drop from the battery.

You didn't mention it, but while you've got the harness apart, inspect the wires to make sure they're all in good shape. Especially look for chafed insulation where it may have rubbed on the frame, or heat-damaged (brittle) insulation near the head. Look for corrosion near connectors making the wire brittle too. I once lost power to a coil when an brittle wire broke off where it entered the coil. Oh, and bypass the stator leg loop that goes up to the connector under the tank, if you have one.

Best. Advice. Ever.

That about sums it all up right there.

[Steve]

Most motorcyles have a large voltage drop in the ignition switch circuit and in many cases this is the main loss so that addressing this problem negates the need for headlight relays.

For this reason, more than any other, I suggest using the stock orange wire from the ignition switch to trigger a relay that powers the fuse box.
Might require relocation of the charge wire from the R/R, but provides good, clean power to the bike.

I keyed in on this and looked at my harness today. Yes I believe I do have that loop. White wire with a red stripe that runs up through the harness under the tank and loops through the 9 pin connector into a white wire that has a green stripe and then back down to the stator. Is that what you are talking about?

How would I go about bypassing this loop? What's the purpose of it?

I would have to replace these wires anyway. They are fried.

Yes, that is the loop.

How to bypass? Easy. Find the stator wire that feeds the loop (white/red), then find the R/R wire that is fed by the loop (white/green). Disconnect the loop, connect the stator wire directly to the R/R wire.

The purpose? Back when bikes still had headlights with switches, that loop actually went all the way to the headlight switch on the left side of the handlebars. There, it went through a second set of contacts that would open and close at the same time as the battery power to the headlight. When you turned the light off, you did not need as much charging capacity, so one leg of the stator was removed from the circuit. When headlights were mandated to be ON all the time (in some markets), they changed just the short harness from under the tank to the switch, and left the "loop" for the rest of the world market that still had the ability to think for themselves.

.

[Good Times]

For this reason, more than any other, I suggest using the stock orange wire from the ignition switch to trigger a relay that powers the fuse box.
Might require relocation of the charge wire from the R/R, but provides good, clean power to the bike.



Yes, that is the loop.

How to bypass? Easy. Find the stator wire that feeds the loop (white/red), then find the R/R wire that is fed by the loop (white/green). Disconnect the loop, connect the stator wire directly to the R/R wire.

The purpose? Back when bikes still had headlights with switches, that loop actually went all the way to the headlight switch on the left side of the handlebars. There, it went through a second set of contacts that would open and close at the same time as the battery power to the headlight. When you turned the light off, you did not need as much charging capacity, so one leg of the stator was removed from the circuit. When headlights were mandated to be ON all the time (in some markets), they changed just the short harness from under the tank to the switch, and left the "loop" for the rest of the world market that still had the ability to think for themselves.

.

Thanks Steve. You're a big help. Everything makes sense when you know a little history. I was sitting there today after following that loop though the harness thinking, "Why in the world would they just put a loop in this harness?" I also remember seeing the wire that jumped that circuit on the connector when I first bought the bike and thinking, "That doesn't look right." I thought the PO had done some creative wiring.

Now let me repeat what you are saying and make sure I've got it right. I currently do not have my stator hooked up to anything. Just looking at my harness out in the wide open space of the garage. Am I correct in thinking that I now just literally take that loop out of the harness and just hook up my remaining three stator wires to the RR?