Cleaning connections/weak headlight

[Guest]

I've been going though the harness and shooting contact cleaner onto all the bullet connectors I can find and recoating with dielectric grease. I've still got to do some under tank stuff and the headlight bucket. I've found 3 square connectors are there any more of the large harness connectors around or is just those three? I need to get into the fuse box as well and clean those connections up. Even after stator replacement and R/R upgrade I've still got a somewhat weak (it's also new) headlight.

I picked up a voltage monitor which is just a large LED light that flashes or stays solid depending on voltage status. I hooked it up in the headlight bucket and with a 14 volt reading at the battery it's flashing 4 times pause 4 times at me which by that led's install instructions means I'm losing 3 or so volts between the battery and the bucket.

[Steve]

Sorry, but it's time to invest a bit more time and money into your project.

For diagnosing stuff like that, you need an actual voltmeter. Decent meters are available rather inexpensively, better meters will cost a bit more, you shouldn't have to pay more than $20.

Also, to clean the connections, you will need to put in a bit more effort than spritzing some connections. You really need to take the connectors apart, brush the terminals, using your spray to flush the crud, THEN apply the dielectric grease.

Start using your (new) voltmeter at the battery, check the voltage. Follow the wiring harness to every connection until you get to the headlight, you will see exactly where you are dropping voltage.
Highlights on your trip should include:
- battery
- hot side of MAIN fuse
- dead side of MAIN fuse
- red wire going into ignition switch
- orange wire coming out of ignition switch
- hot side of LIGHTS fuse
- dead side of LIGHTS fuse
- both sides of connector leading to beam selector switch
- connector on back of headlight.

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[Downs]

I've got a FLUKE multimeter I just forgot to grab 9V batteries last time I was at the store and forgot to turn it off last time I used it so it's currently dead. I'll start shooting wires after I get of shift tomorrow.

[Redman]

And a stock headlight (sealed beam) on a 78 is going to look weak compared to a headlight from the 80 (Halogen) or later.

Good that you have a good meter.
WHen measuring voltage at some particular thing, say, headlight, do measure the voltage at the head light with the meter positive lead on the headlight and the negitive lead on the headlight ground wire, so that you are measuring the voltage AT the headlight. If it measures what you think is low, then move the negitive lead to the ground or battery negitive, if that measures good, then you know is a problem in the ground wiring to the headlight.
Or.... if you really want to leave the meter negitive on the ground while testing various things by moving the meter positive around, that is okay. But if measure good voltage somewhere, say, the headlight, before you condemn the headlight because it is not working, do move the meter negitive lead to the headlight and measure voltage again.

[Fjbj40]

If you want a bright headlight then do a relay install. Too much power goes through the switches including the ignition switch. On these old bikes they are a cause of voltage loss, often you will find them burnt or semi-melted. I eliminated all that by doing relay installs. I get a full 12+ volts at all my items I have relayed. Not only do I get full voltage I get very good current, voltage means nothing if you don't have good current.

A test light checking connections also shows current as it puts a load on what you are checking. A cheap incandescent test light along with a meter is the best testing technique, IMOP.

Cheers

[solarae]

A little piece of rolled up, fine grit sandpaper inside the bullet connectors can work wonders too. Not that a relay doesn't sound like a great idea.

[CaveMan]

I too am having a electrical problem but it is not a dull head light my turn signals they come on but wont blink. I have the 3 prong relay

[Downs]

And a stock headlight (sealed beam) on a 78 is going to look weak compared to a headlight from the 80 (Halogen) or later.

Good that you have a good meter.
WHen measuring voltage at some particular thing, say, headlight, do measure the voltage at the head light with the meter positive lead on the headlight and the negitive lead on the headlight ground wire, so that you are measuring the voltage AT the headlight. If it measures what you think is low, then move the negitive lead to the ground or battery negitive, if that measures good, then you know is a problem in the ground wiring to the headlight.
Or.... if you really want to leave the meter negitive on the ground while testing various things by moving the meter positive around, that is okay. But if measure good voltage somewhere, say, the headlight, before you condemn the headlight because it is not working, do move the meter negitive lead to the headlight and measure voltage again.

It's got a brand new Sylvania Silverstar on it. Far better than the original as far as brightness but it looks like it should be brighter. I thought it was a sealed headlight as well till I pulled it apart and the stock headlight that came out of it has a H4 style replaceable bulb in the back.

I too am having a electrical problem but it is not a dull head light my turn signals they come on but wont blink. I have the 3 prong relay

Might just be a bad relay. What year is your bike? Blinker relays are pretty cheap.

[salty_monk]

The ignition switch has been the primary culprit in my experience. Relays can help as other have said but you need to run additional wires. Do the coils too whilst you're at it...
Also note on the 78 the connections in the back of the fusebox can become loose &/or break strand by strand. I re-soldered mine & then back filled it with epoxy before putting the cover back on after it happened on a roadtrip...

[Steve]

Yeah, it's relatively easy to add a relay here, add another relay there, etc., etc. I have found it's easier and just as good, if not better, to just use ONE relay.

Interrupt the orange wire from the ignition switch to the fuse box. Connect those two wires to a relay. Assuming the standard "Bosch-type" relay, connect the switch wire to terminal 85, the fusebox wire to 87. Run a fused wire from the battery (I actually use the battery terminal on the starter solenoid) to terminal 30, connect a ground wire to 86. Doing this, you have full battery voltage going to the fusebox, and the load on the ignition switch terminals has been reduced to just turning on the relay. One other thing that has to be done is to re-route the output of the R/R directly to the battery (using a fuse, of course).

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