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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: cameroneod on September 16, 2015, 07:58:43 PM
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First of all, a big thank you to everyone who has posted their problems and solutions here in the past. It's given me some direction at least.
So, here's the deal.
My headlights, horn, blinkers, windscreen, etc., were not working. After reading about common problems on here, I tore it down and yanked the starter. It didn't look bad at all. Not much carbon build up and the brushes are just fine. I cleaned it all up anyway and reinstalled.
Now the spraque clutch will not engage. I picked up some diesel oil and engine treatment and I believe I'm on the right track with getting that figured out.
We push started the bike and ran the hell out of it. Brought it back to the house and got it up on the center stand, then let it idle for a while. While sitting there I put it in gear and ran it up to around 6k. Low and behold, the blinkers started working, but only at high rpm's. The headlights never did come on and the brake lights wouldn't work either.
Am I right in thinking this may be an alternator problem? Im not sure what the alternator is putting out because I left my multi-meter at work, but I'll grab it tomorrow and check it out.
Am I on the right track? Totally off base? Someone lead me in the right direction!
I appreciate any help I can get.
:mm
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Sounds like the load shed relay is open, as in no ground for it to close. The ground is made thru the starter windings when it's not turning to start....
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If that is the case, why would the blinkers work at high rpm's?
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Don't know the full scientific reason as to "why". But my k100 4v did the same thing when my starter went out.
Reason I read was that it is due to how the current grounds through the starter.
Btw, the brushes will "look" ok but the one that bolts in is deceptive as to how close to tolerance it is.
Am still thinking as to other possibilities, just wanted to let you know that the no lights until high rev was a big sympton.
Later,
Freelancer
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All I can say at this point, is that the flasher module is fed with 2 sources of +12 power. 1 is thru the load shed relay(fuse #7), the other is direct from the battery(fuse #3).
I don't know the internal circuitry of the flasher module to know if the input power can bleed over from one input to the other under the conditions you listed, but with no headlight, brake lights and no horn, the LSR is open.
The 2 main battery ground connections are at the center frame tube under the fuel tank, and at the starter mounting bolt.
Wouldn't hurt to double check and make sure they are clean and tight, most likely they are fine, but at least then you can eliminate them from the questionable list.
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I cleaned off the grounding points with steel wool and reassembled with dielectric grease. I'm fairly certain I have a good ground, but now that I've read some horror stories Im wondering if I've got a backwards spinning starter. :euro
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I'vr done that so I guess I have to wear that hat and moustache too. But I don't remember it affecting the lights -- maybe I was so concerned the thing wouldn't start I didn't even look at the lights. Why would it running backwards affect whether it's making ground or not?
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Why would it running backwards affect whether it's making ground or not?
It wouldn't. It would still make the ground reference for the LSR to function.
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Two different problems. Even if I could get the sprague clutch to engage I'd still be left with the original "no lights" problem. I've got a set of brushes I'm going to install when I take it back apart this evening. I measured the ones in the starter and they are OK, but I can at least check that off the list.
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When my starter began to need brushes I remember the headlight still working but the running lights were flickering. I don't know if this info helps or not but I figured I'd put it out there
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It'd be great if it were the brushes. That's a really simple fix, and I'm not ruling it out, it just doesn't seem likely. I still don't understand exactly how the electronics work on this bike, but issues like this will school you quick.
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Before you start thinking about addressing the sprag clutch, I would recommend making sure the starter is in fact turning the right way. If it ceased starting after you disassembled and reassembled the starter -- that's a big indicator that you may have reassembled it backwards. It's easy to do and easy to fix -- just pull the starter again and flip the housing around. Search for my thread about just that from -- 2013 I think it was. How I agonized...all because I wasn't paying attention at the bench...
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Im hoping that is the problem. Worst comes to worse, I treated an engine with Rislone that didn't need it.
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OK, starter is back in (correctly) and spinning in the proper direction! :hehehe New brushes are installed and I cleaned up the grounds at the starter (again) and the other by the frame. Still no lights, horn, etc. What am I missing?
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Your load shed relay may be bad. Have you tried replacing it yet? There may be one that you can swap with one that is already in the bike. Someone here should know if you can swap it with another relay. I'm not familiar with the relay layout on the K-bikes. I've had very little reason to learn the layout in the 128K miles I have owned my K100LT.
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I have not tried replacing it. I did have a look at the electrical diagrams in the shop manual I downloaded. Might as well be Chinese. :dunno2:
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Looking at the diagram I believe that the load shed relay is the same as the horn relay. Is that right, or no?
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It's most likely that you won't be able to tell from the diagram. The difference in the relays is likely to be current capacity. The diagram will not list the capacity. Just look to see if the part number is the same.
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Horn and LSR should be interchangable. Same p/n in realOEM.
The way that the load shed relay works is confusing but in fact cleaver.
The relay coil is fed with the positive(+) from the ignition switch on one side and from the ground(-) coming from the starter on the other side(the ground is passing through the inductor of the starter motor). when you push on the starter button, this ground will be switched to positive and the load shed relay coil will then be fed by a positive(+) on both sides (Equal potential on both sides of the coil is like not having power). At this point, the load shed relay will be released and the lights and accessories will go off.
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IT IS FIXED!
:clap: :clap: :clap: :clap: :clap: :clap: :clap: :clap: :clap: :clap: :clap:
I swapped around the load shedding relay and the horn relay. Lights came on immediately. I didn't expect the horn to work so it gave me quite the jolt when it worked. :yow
Must have been a bad connection.
A big thank you to everyone who replied and lent advice. The beer is on me if you are ever in WNC. Maybe hit up the Tail of the Dragon. :D
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Horn and LSR should be interchangable. Same p/n in realOEM.
The way that the load shed relay works is confusing but in fact cleaver.
The relay coil is fed with the positive(+) from the ignition switch on one side and from the ground(-) coming from the starter on the other side(the ground is passing through the inductor of the starter motor). when you push on the starter button, this ground will be switched to positive and the load shed relay coil will then be fed by a positive(+) on both sides (Equal potential on both sides of the coil is like not having power). At this point, the load shed relay will be released and the lights and accessories will go off.
RBM,
You are awesome. Even though this isn't my thread, I want to thank you for posting the quoted explanation.
It is very useful to know that these bikes have some Lucas style positive grounding circuits in them.
I knew that the circuit grounded through the starter but not that there was a positive ground at the LSR.
@cameroneod,
Congrats on the fix. Looking forward to seeing what the fully modded bike looks like.
Best of Luck,
Freelancer
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That's really not a positive GROUND at the LSR. For a connection to be considered grounded it must be hooked up to ground. Ground is negative on these bikes. In the explanation of how the circuit works it is explained as being hooked to the plus side of the battery when the starter is energized. The plus side of the battery is NEVER grounded during this operation of the starter relay. I prefer to think of the LSR and starter as a series circuit when the starter relay is not energized. Since the LSR coil has such a high resistance as compared to the starter winding, just about all of the voltage will appear across the LSR coil with a minimal voltage across the starter winding. The LSR relay coil is never truly grounded since the starter winding is always between the negative side of the coil and true ground.
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Freelancer,
Kioolt is right. This is not a positive grounded circuit; it's more of a voltage-controlled relay. Relays work when a potential difference in voltage appears across their coils. When the bike is off, the difference in potential across the coil is 0V; one side is ground potential and the other side is 0V. In this case with the LSR, the difference is again zero volts because each side of the coil has +12V potential. So, 12V - 12V = 0V.
The same principle holds for the charge indicator light. When you first turn on the ignition, the potential across the charge light is 12V (battery potential on one side and ground potential on the other side. The charge light lights up. When the engine revs up, the alternator applies 14V to the battery and the rotor gets the same potential induced. The potential across the light is then battery potential of 14V on one side and 14V on the other side. So, 14V - 14V = 0V. The charge light turns off.
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@ Kioolt & rbm
Thank you both for the correction and clear explanation of the differences. Such knowledge and kindly instruction are a large part of why many come here. :2thumbup:
....The other part is Johnny's and a few others unique brand of humor :hehehe
At some point I'm going to dive back into my K100RS project. When it comes time to wire in the K1200rs speedo into the older motronic/custom harness expect a few questions.
Thanks again guys,
Freelancer