Headlight tweaking

[Thursty]

Im still trying to dial in my bike, which seems like a never ending process. Id have it no other way. Since my last post, i got the blinkers working (new relay is all it took), and with the new wiring installed, the bike was good to go.

Upon getting the bike on the road, and wctually getting to spend some time on it, i noticed that the headlight would tweak out after about 45 mins to an hour of riding. This tweaking never starts until after about 45 mins! Sometimes the tail light flickers a bit too, but mostly just the tail light. Ill insert a video link here to share what im talking about, and address any questions in regards to what i have, and jave not done to address the problem. I will be working on the bike today, and cleaning up the wiring harness modifications i made, to ensure that isn't the problem.

I will also note that i was periodically burning fuses for a bit, and 'trial and error' eliminating specific circuits to identify the source of the problem. I since have disconnected my blinkers, and not burnt a fuse since. Because i ran out of 20 amp fuses, i installed a 15a fuse and havent burnt it out yet, since disconnecting the blinker circuit - from the relay forward.

 

[Thursty]

 

[jpdevol]

I dunno what your wiring harness consists of, but it appears you 're having an intermittent problem on the headlight circuit that is most likely a poor connection at some point. One of those points may be the dimmer switch (Hi/Low switch) on the handlebar may be dirty or have a bad solder point.

The signals blowing fuses indicates a hot wire is shorting to ground somewhere ahead of the bulb. Likewise, if you're running the original bar switch, it could be that the brown/white wire inside the switch is loose and shorting to ground there (among other places)

 

[Thursty]

I actually bypassed the hi lo switch for a bit to test if that was the problem, and it still tweaked out. Im pretty sure the previous owner has the headlight wired into the safety relay, so the bike only has power to the headlight when running, as its powered by the generator? Electrical/mechanical/motorcycles are all pretty new to me, so i could be all confused. Ill post a pic of where headlight power comes from... If this is the case, why would the tail light 'occassionally' tweak aswell, if its on a different circuit?

 

[Thursty]

Also the reason for this, i believe, is because the previous owner eliminated the meter bracket and everything else electronic with it... He had the ignition system wired into a toggle switch, and bike is kick only. The reason i replaced his harness was to install flashers. However, wanted to keep the bike as close to how he left it as possible. It was untouched since 82 and heavily influenced by 60s/70s chopper culture. Which is why i copied his set up in regards to the toggle switch set up.

 

[mrtwowheel]

I second the handle bar switch. Probably needs cleaning anyways. Those switches have contacts that are as small as the head of a pin and any corrosion, dirt or road grime can cause intermittent contact.

 

[Team Junk]

Check your ground on the headlight and battery.

 

[Team Junk]

Check your ground on the headlight and battery.

 

[mrtwowheel]

After your last two posts #4 and #5............I'm thinking that the taillight and headlight are sharing the same ground connection and that may be where your intermittent connection may be.

 

[mrtwowheel]

Team Junk beat me to the ground. call 911

 

[Thursty]

 

[Thursty]

Also wondering why the tweaking only happens after the bike has been running for awhile. Like 30-60 mins? Could a ground still be the cause of this?

 

[mrtwowheel]

yep, temperature, vibrations

 

[jpdevol]

It is possible to have an intermittent bad ground - it would be unusual for it to be time/heat related.

On a custom wired bike, it's difficult to tell - particularly if the original "light checker" and "reserve lighting unit" have been removed - how the headlight circuit is wired. The "Safety Relay" didn't control the headlight circuit until '78 on US models; I believe it may have on '76 Canadian models, but that was on the blue/black wire from the relay and not the red/white wire. The red/white circuit should open (disable) when power is present from the alternator on the yellow wire from the stator to the Safety Relay and the blue/black wire is then powered to the headlight. Normally on a kick-only rewire, the safety relay is eliminated as it's primary function was to disable the starter once running.

If the tail light intermittent "tweaking" happens simultaneous with the headlight tweaking, then the ground is suspect. If not, then it would seem to be two different bad connections on the positive side

 

[Thursty]

yep, temperature, vibrations

Awesome, thanks for the advice! I rerouted the battery ground as i noticed it had a tight bind near the connection and was showing signs of rubbing on the side cover. Not that this will resolve the issue, but is probably good i rerouted it

 

[Thursty]

It is possible to have an intermittent bad ground - it would be unusual for it to be time/heat related.

On a custom wired bike, it's difficult to tell - particularly if the original "light checker" and "reserve lighting unit" have been removed - how the headlight circuit is wired. The "Safety Relay" didn't control the headlight circuit until '78 on US models; I believe it may have on '76 Canadian models, but that was on the blue/black wire from the relay and not the red/white wire. The red/white circuit should open (disable) when power is present from the alternator on the yellow wire from the stator to the Safety Relay and the blue/black wire is then powered to the headlight. Normally on a kick-only rewire, the safety relay is eliminated as it's primary function was to disable the starter once running.

If the tail light intermittent "tweaking" happens simultaneous with the headlight tweaking, then the ground is suspect. If not, then it would seem to be two different bad connections on the positive side

It is a 76 Canadian bike, and when i got it, was as you stated, a blue/black running from the relay. I since switched it out with the fresh white wire. When the tail light has tweaked, its been with the headlight aswell. But 95% of the time its only the headlight tweaking. What do you think i should do? I have a new harness on it with an un-modified ground circuit. Only the ignition circuit has been modified to accommodate the toggle switch ignition circuit.

 

[jpdevol]

Just a guess: If the contacts are dirty inside the Safety Relay, or the soldered connections iffy, that could explain why the issue appears after some riding time. Perhaps take the lid off and clean and check connections inside the relay.

Even if that causes the headlight issue, that doesn't explain the tail light issue; it may be a separate issue. Has the "light checker" and "Reserve light unit" been removed?

 

[mrtwowheel]

You could run a new ground wire, even temporary, for the headlight and taillight, see what happens. In other words......temporary ground wires right to the battery negative.

 

[Thursty]

Just a guess: If the contacts are dirty inside the Safety Relay, or the soldered connections iffy, that could explain why the issue appears after some riding time. Perhaps take the lid off and clean and check connections inside the relay.

Even if that causes the headlight issue, that doesn't explain the tail light issue; it may be a separate issue. Has the "light checker" and "Reserve light unit" been removed?

Since rerouting and cleaning the main battery ground, still has issues after 30-60 mins of riding (as expected). Ill check the contacts inside of the relay next and clean them up. I actually went back and cleaned up my harness modifications in regards to the ignition circuit, and just made sure they were nice clean solders and connections.

If its a ground issue, could i do isolated grounds on certain components to see if that fixes things? Also got another video 30 mins ago when i got back home. When i first arrived, headlight was tweaking, and tail light was out. By the time i started the video, the headlight was good, but tail light still out. I then twisted the throttle a quick second and the tail light came on, and stayed on. Break light worked too. But then as youll see in the video, tail light started to tweak and flicker a bit... So agrivating when its inconsistent and hard to find... Will definitely try cleaning relay connections.

 

[mrtwowheel]

It sounds kind of sick, but I always feel lucky when a problem shows itself to be intermittent. Kind of makes it easier to solve, most of the time that is.