89 K100 RS SE with intermittent dropout on all lighting when at temp and a mild smell of burning electronics for the first 5-6 minutes. I Tore dash and cluster apart assuming I would find obvious signs of burning. Nothing. No char anywhere. I took the tank off and went through entire wiring harness. Only sign of char anywhere is on a wire tag that was underneath all the other wires, near the wiring passthrough above the airbox on the right side of the bike. No other signs of char on any actual wiring or connectors. I am using this as an opportunity to grease all of the connections and since the next step that I can see is to pull the airbox I will replace the cooling fan while I am in there. I will open the left handle bar switch and check all of those connections again, as that may explain the intermittent lighting, but I can't imagine enough char in there to explain the amount of smell. Any suggestions on where to look for signs of burning electronics besides the electronics compartment? 

I am imaging a society of mythical gremlins where the electrical gremlin is the king and all other gremlins bow to him.

Most suspicious is in between the frame on the front and the fork, it has to turn a lot there, wires can get worn there.

I get smells like that too. I decided it is a small amount of oil or grease getting on something hot. It comes & goes . If you were toasting wires you'd be blowing fuses unless you put in higher value fuses.Face it,most of the fuses are 7.5A and the rest are 15 A . I think burning wire would pop those . Just my 2 cents

Depends which lights drop out and if the engine also stalls. I'd look at the green/blue wires from the load shed relay, depending which lights, and the load shed relay. And the white/yellow.

If it only happens after using certain lights (say parker's, high beam, low beam, indicators, hazards, brakes) they would be pointers.

With the engine running for example, the headlight gets unfused power from the load shed relay to the right handlebar connector plug, under the tank. 

With the engine running, the parking lights (and the instrument cluster back lights) get unfused power from that same handlebar plug. With the key in the park position, the parking lights get unfused power from the ignition switch, but without power to the back lights, as a battery saving feature. So removing the load shed relay with the key in park, might help narrow the search. 

If the smell disappears after removing the load shed relay, that narrows it down. Or feeling if it gets warm, or swapping it with the horn relay. 

If running on the centre stand, you might see a small amount of smoke to help locate it.

daveyson wrote:Depends which lights drop out and if the engine also stalls. I'd look at the green/blue wires from the load shed relay, depending which lights, and the load shed relay. And the white/yellow.

If it only happens after using certain lights (say parker's, high beam, low beam, indicators, hazards, brakes) they would be pointers.

With the engine running for example, the headlight gets unfused power from the load shed relay to the right handlebar connector plug, under the tank. 

With the engine running, the parking lights (and the instrument cluster back lights) get unfused power from that same handlebar plug. With the key in the park position, the parking lights get unfused power from the ignition switch, but without power to the back lights, as a battery saving feature. So removing the load shed relay with the key in park, might help narrow the search. 

If the smell disappears after removing the load shed relay, that narrows it down. Or feeling if it gets warm, or swapping it with the horn relay. 

If running on the centre stand, you might see a small amount of smoke to help locate it.

Thanks for the reply. Here is the update after working on the problem Saturday, thinking I had it fixed, only to be forced to drive the truck this morning when all the lighting dropped out as I was backing out of the garage. It seems to be universal lighting all drops out at the same time. It powers on normally when I start the bike, then flickers to darkness. If I rev the engine it brightens up momentarily and once the revs drop below 2K it flickers out again. I will be short on time again this week and through the weekend, but will try swapping the load shed relay with the horn relay and see if the problem follows the relay. Oh, and the sprag clutch is acting up. If I can get the electrical figured out enough to ride it safely I will do an oil swap to rotella. The lighting problem seems to operate the same whether the engine is running or not, and there is no change in revs as the lights fade to black.

P.S. I thought i had fixed it this weekend when I overhauled the left hand handlebar controls, the light switch seemed glitchy, and after cleaning and di-electric greasing it seemed much nicer to the touch.

What's the resting voltage of the battery?

Laitch wrote:What's the resting voltage of the battery?

I don't think it is the battery, as I replaced it in June of 20 with a brand new sealed unit, and it starts the engine with no problems. But I will check after work today and report back.

Battery resting voltage is 13.48. Seems good to me, but maybe it should be something else?  It turns the engine over well. I swapped the load shed relay with the horn relay. problem was not solved. I will be replacing the starter next, along with the relay just for good measure. I usually ride the bike daily and need it to be reliable. Another thing I noticed while testing last night is that the lighting drop out is semi RPM dependent. IF i rev it up to 4K the lights will come on and stay on until 2K sometimes, once I even had the light stay on while idling. it is not very consistent aside form the fact that increased rev usually mean the lights will come on, except for sometimes. I took a video, but can't seem to upload it. thanks.

KlaustheK wrote:Battery resting voltage is 13.48. Seems good to me,  but maybe it should be something else?. . . I will be replacing the starter next . . .I took a video, but can't seem to upload it. thanks.

That's good voltage and within specs widely published here and elsewhere. If the starter works, replacement seems unnecessary. Does the engine still emitting an odor like something burning when it's running?

About posting a video here: 
You upload a video to YouTube, choose to make it available publicly then post it and give us the YouTube link.

KlaustheK wrote:The lighting problem seems to operate the same whether the engine is running or not, and there is no change in revs as the lights fade to black.

Does that mean when you turn the ignition switch to On but do not press the starter button, the headlight and instrument warning lights illuminate but then flicker and eventually shut off?

Laitch- I should have been more clear. When first observed, the issue only presented when the engine was running. during testing Monday night the lighting fault continued after the engine was shut down. I think the burning smell is just oil burning off, I discovered a small oil leak. I swapped the horn relay with the load shed relay, I think, and there was no change. I swapped the front right relay with the relay directly to the rear of the bike from there. The diagram I found showed these to be the horn and load shed relays. Do you think that is still most likely? I'll try to post the video on YouTube tonight. I can't do that from work. I was thinking the starter due to other research on posts found here, doesn't the lighting find ground through the starter?

When you remove the horn relay the lights will work but the horn won't. When you remove the load shed relay the lights and the horn won't work. The load shed clicks with ignition on, but won't if it's removed. 

The load shed provides power, not earth, to the lights and horn. If for example the start button was faulty, turning off the load shed, and power to the lights, then the starter would be spinning when your lights turn out, so I'm guessing that's not your problem.

The lights might work after swapping the relays, but your problem happens say five minutes after running.

Video of the fault in action while bike is running.
More testing tonight. When engine is off, lighting and horn are normal. When engine is running lights do not operate normally. Tried swapping load shed and horn relay again tonight, thinking maybe I didn't actually swap them last time. No change. With either relay in the load shed position the problem persisted.

Just an idea from left field - how are the brushes on the voltage regulator?

Could be a poor connection. I'd remove the load shed relay and run it for ten minutes to see if the smell problem is gone. With the load shed relay replaced, and after ten minutes of running, you might be able to feel a warm connection or load shed relay or something. I was thinking maybe the right handlebar connector plug (under the tank) cause you mentioned signs of burning on the right side. Would be interesting to see how that plug is permanently jumped in US models. Maybe check for Voltage drop across different connectors.

If the flasher cuts out with the headlight, maybe look at the green/blue wire from the load shed to the left handlebar plug. If not maybe look at the green/blue wire from the left handlebar plug to the right, because the instrument cluster back lights (connected with the parking lights circuit when the key is in the on position) also fail with the headlight.


If the horn fails (or the indicators) at the same time the headlight and backlights fail, that points to the load shed relay, or it's connections.

Doh, I think I've been over thinking this pretty bad, your right, with an earth failure at the starter motor, your lights will cut out. But that wouldn't cause a smell,  and you would have probably had failed attempts at starting where the starter simply wouldn't spin. I've had worn starter brushes but that just meant the starter wouldn't spin. 

Another test, with a test light at the starter motor terminal, if the test light goes out at the same time as the headlight, the starter is failing to give earth. If the test light remains on, check for earth at pin 85 of the load shed relay.

daveyson wrote:Doh, I think I've been over thinking this pretty bad, your right, with an earth failure at the starter motor, your lights will cut out. But that wouldn't cause a smell,  and you would have probably had failed attempts at starting where the starter simply wouldn't spin. I've had worn starter brushes but that just meant the starter wouldn't spin. 

Another test, with a test light at the starter motor terminal, if the test light goes out at the same time as the headlight, the starter is failing to give earth. If the test light remains on, check for earth at pin 85 of the load shed relay.

Thanks daveyson! That is excellent. Unfortunately I won’t be able to try it until first Saturday in October. I will let you know what I find.

Glorious Victory!!! The old starter had 14 ohms resistance across it. Not a great ground. I’m amazed I had lights at all. I installed the new starter and put it all back together. First ride in three weeks! So dang good. Klaus lives! I could have saved myself two weeks of suffering if I would have just checked resistance between the starter terminal and ground three weeks ago. The cost of the starter will be covered with three weeks of commuting. Commuting in my truck is not very economical.

Bonus, it's good when you can fix it yourself, rather than take to a mechanic to pay for it. The starter is easy to open up, the brushes might be beyond their useful limit, or one of them. 

On a less important note, I think the top (inner)  speedo back light has gone, so you only have one left (bottom, outer) The speedo back lights are more important than the clock or tacho back lights, I'm thinking, in case you go into the instrument cluster again.

daveyson wrote:Bonus, it's good when you can fix it yourself, rather than take to a mechanic to pay for it. The starter is easy to open up, the brushes might be beyond their useful limit, or one of them. 

On a less important note, I think the top (inner)  speedo back light has gone, so you only have one left (bottom, outer) The speedo back lights are more important than the clock or tacho back lights, I'm thinking, in case you go into the instrument cluster again.

The old starter actually had 3-4mm linear play in the shaft. I thought about replacing the brushes but I’m glad I ordered the replacement as new brushes wouldn’t have fixed the loose bearings. 

As far as the speedo light, I plan on refreshing the cluster this winter, but I find the speedo to be the least important gauge. It’s only good for telling how mad “the governor” would be if she knew. I tend to go as fast as the bikes says I should, which is typically in excess of the posted “recommended speed”

So many problems can be avoided by maintaining good earth connections.
Glad you got it sorted.