Electrical problems 1980 GS850L

[Anonymous]

Hey all. Been hard at work trying to put my newly acquired GS850L back together. The girl took fire damage and is slowly coming back around. Here's the problem...

All the electrical worked when I brought her home. But, the wiring around the coils was all damaged - including the connectors. The 9 point connectors for the instruments were melted together so badly that they had to be cut apart to seperate them from the harness. The insulation was badly damaged from the front of the tank back to the battery box. And considering the look of the breather box, I would assume that it originated there.

So, I replaced the wiring harness on Friday. I was careful making sure that every connection was solid and tight and that all grounds were minded. When I slapped the battery in, the only thing I got power to, apparently, was the neutral light and the horn. And this is where the fun begins.

I went back through and reconnected all the junction points. Every connector was disconnected, cleaned and reconnected. After that was done, my oil indicator light came on. Progress. The starter switch isn't working and the previous owner had jury-rigged another. That worked before the harness change. It currently does not. I have the replacement to fix the switch; but, it should still start off the workaround. I shorted across the posts on the solenoid to make sure it wasn't a power issue - the starter cranked over normally. So it doesn't appear to be power.

Next on my trip around the bike, I decided to check for power across the
fuse box. When I tested the bottom most fuse on the block, nothing seemed to happen - power was normal; but, when I touched positive to the second from the bottom and grounded the other end of the tester against the frame, I suddenly had rear running lights. The brake light had been working since the change over on the harness; but, I hadn't had running lights. I also noticed that my hi/low beam indicator was now on. So, I decided to check the blinkers which hadn't worked since the change. They work - sortof.
My front left and rear right blinkers come on and stay on. The front right and rear left will not come on at all.. no matter what I have tried. I swapped out the blinker module with a known good module and there is no change.

So, long story short, I can't get the starter switch to function and my blinkers are only halfway working. Since this came about, I can turn power to the bike off and on without any change - everything still works.
And the latest addition is the instrument backlights for the front gauges.
My gut is telling me there is a loose connection or a bad ground somewhere; but, I'm stumped as to where to go from here.. at least for the moment. I've never had to troubleshoot an issue like this before - just been lucky I guess. And, incidentally, the wiring diagram provided in the clymers SUCKS hugely. The color codes don't all match, and the diagram is less than useful IMO. Tempted to write up my own along with a technical brief for changing out a harness when this is all done. I can now pretty much change one blindfolded.

Thanks for the help in advance. Looking forward to any input.

[Anonymous]

First you will need like 3 sets of hands to try this...
What you should first try is checking for 12 volts at the yellow wire that triggers the starter solenoid, the little solder joint on top will do, to do this you need the start switch set to run, if you have a starter safety switch you need to engage the clutch to close the safety switch and then hit the start button, that closes the circuit to send 12 volts to the solenoid. If you are getting 12 volts the solenoid might not be grounded properly. I found on my bike the battery box is insulated with a rubber bushing on the front and rubber mounts in the back and the whole box is not grounded. The solenoid ground is the body of the solenoid itself, there is no ground wire on the solenoid itself. There is the large heavy wire from the starter and the red positive from the battery directly. I had to run a ground wire from the engine to the mount screw on the solenoid, bingo problem solved.
The circuit for the starter circuit is very simple.
When you have the clutch engaged the start switch set to run, the ignition on and the start button pressed that completes the circuit to the solenoids little yellow wire, that solenoid closes and sends positive voltage from the battery directly to the starter. If you take a large insulated screwdriver and cross the 2 large terminals on top of the solenoid the starter should crank if the battery is good. That solenoid needs to be grounded and the screws into the side plate are not enough if that battery box is insulated and doesn't have a proper ground.
I thought I had a stuck solenoid when I found the 12 volts on my solenoid, the second I grounded the body on the solenoid the starter fired right over. Sounds like you did that when you touched a ground testing the fuse panel which is attached to the battery box not grounded. Ground that battery box and it should solve some problems...
Bill Rycraft...

[Anonymous]

Battery box ground

Thank you. Will try it after work tonight and let you know.

I spent all day today working on both the bikes and both are progressing.
Rebuilt the carbs for the G today and she's pretty much road ready now.
The L got a nice fresh frame today which I promptly went to work cleaning and painting. She'll get several gloss coats after work, then I'll begin rebuilding onto the new frame. She's gonna look like a new bike; but, perhaps not stock The biggest roadblock right now is the electrical, so, I really hope this works lol. Thanks again.

[duaneage]

On something like this I would suggest using a zoned approach.

First get the starter solenoid and charging section working. This is the unfused high power side of the bike.

After that is done, remove the fuses and start with one circuit at a time. Put a fuse in and using the wiring diagram make sure you get each item on a fuse working. You can connect a voltmeter as a ampmeter to measure current by placing the red lead on the supply side of the fuse holder and the black on the other. The red lead will probably go into a different socket on the meter to measure current. Remove the fuse and the voltmeter ( now ampmeter) completes the circuit and if you have a short the higher current it draws will be apparent.

Good luck and I hope it works out. Many would just part a bike out rather than spend the time on electrical stuff like this.

[Anonymous]

If you do that just make sure you set your meter to Amps otherwise you can destroy your meter.

[Anonymous]

..Good luck and I hope it works out. Many would just part a bike out rather than spend the time on electrical stuff like this.

Thanks for the input. I'm standing by for a second set of hands to test the starter circuit. But, I did manage to find the problem with the blinker circuit..
Seems the thing initially worked because there were two tenative connections inside the non-working blinkers. The grounds inside the units were not tight.
Problem there is now fixed and I have a full set of working blinkers. The trade off there is that I noticed that the front brake switch isn't working and I'm not sure if it was that way to begin with. So, one problem fixed, another surfaces.. lol. Anyway, gonna go spray the frame with another coat of clear. She's looking better all the time

Oh, and a lot of people might part out a bike like this; but, I'd rather give her a chance first. Most would part her out because they neither have the patience, will nor use for a little hard work IMO. Nobody fixes anything anymore in our throw-away culture. If it takes more than 2 minutes for their bigmac to be delivered, they're up in arms. How else are they gonna react to a project that may take them months to see real progress on...

Another note, for those interested in following progress of the rebuild, I've started a page on my website linked from the main that will track the progress of the build. Haven't posted all the pics yet; but, just got it up there tonight and am working on getting the pics downsized to stay within limits.

[Anonymous]

The front brake is controlled by to wires orange/green stripe and white. They could terminate inside your headlamp but is easy enough to trace from under the right hand brake switch. disconnect the wires, set the meter to ohms or better yet diode check if you have it that gives an audible beep on the meter when continuity is made. Close the switch and see if the switch is in fact closing, that is the first step, if ithe switch is not making inside the switch is a small post that looks like a square martini glass with a plastic post for a base with a brass cover that is spring loaded so be careful when you remove it that is inside the brake switch, that tiny spring can fly out and is impossible to find, that post rides back and forth and the spring loaded copper cover is what is held against the back of the switch, when it makes contact with the 2 copper rails on the switch it turns on the lamp., sometimes they get corroded and a light buffing with an emery board clears them right up, or you can loosen the screws and slide the switch slightly sideways to adjust the switch. If the switch is in fact closing then it is a wire chase. Orange/Green wire goes to the 2nd fuse from the top on the right side of the fuse block, the white wire ties in with the rear brake switch and goes to the tail lamp where it goes through the lamp to ground. Easy circuit to chase. Just a matter of getting out the meter...
I agree with you in a world of instant gratification, the I want it now generation wouldn't take the time they would just buy a new one. I have been working 9 months on my bike trying to get it back on the road after sitting in a garage for over 2 years. Anyone can buy new with credit but it takes patience and talent to bring one back from the dead. That is what makes these old bikes so classic, it is what it takes to get them there and keep them running. More satifaction from hard work and sweat then from walking into a bike store and signing your life away....

[Anonymous]

Ok, still haven't had a spare set of hands around; but, I'm working to solve another problem for the moment. What I can say is that the battery box isn't properly grounded and that may be contributing.

I checked the box and tried grounding it; but, the box in the bike now is nothing but a pile of rust. Grounding it has thus far granted me nothing.
But, I found that the main line running from the solinoid to the starter is not
in the greatest of shape either. The casing is cooked. So I bought another
a few days ago, along with a new brake switch assembly as it was cooked too. I have a small pile of parts to put in place before checking again; but, feel I'm making progress anyway. The main line to the starter appeared to have a break in it causing a short. At the least, it's a contributing factor. I don't think it's the whole problem though. We'll see.

In the meantime, I'm keeping the new webpage updated with current changes and pics. And I'll keep ya'll posted as to the outcome.

The site is http://home.insightbb.com/~havoc/project.html

Thanks again

[argonsagas]

[quote="BRycraft"]with a plastic post for a base with a brass cover that is spring loaded so be careful when you remove it that is inside the brake switch, that tiny spring can fly out and is impossible to quote]



Small tip for you:

(helps to save all those springs and other tiny parts)

When you plan on working on any switch on your bike, first visit a grocery store and get one of their clear plastic vegetable bags. Cover the switch and surrounding area, and work inside it.

You can see through the bag and they are usually large enough to afford space for your hands and small tools.


Another suggestion.

A common problem that leads to poor electrical flow is not visible, but is hidden in the fuse box. Connectors inside get dirty, corrode, and the normal current flow can cause overheating. (I had one melt)

Remove the fuse box and take it apart. There is a removeable panel at the back and you should be able to pry it off with a screwdriver. If not, then an X-acto type knife will do the job and the piece can be glued back.

Note the positions of parts, then remove and clean all connections and replace them and the panel.


If you continue to have problems with circuits you may want to look into the harness. The orange/green wires....(if they are the same as on my bike) are factory-spliced several times inside the harness, and those crimp connectors can loosen or fail, even though they are not exposed to weather.

If I recall correctly, there are eight splices inside the harness.

Your ohmmeter will work only so far due to the splices, so, if you go that route, it will also give you an opportunity to isolate circuits that cannot otherwise be accurately checked.

[Anonymous]

Thanks for the tip on the baggie. A buddy blew the springs to his blinker switch to oblivion so I was prepared for that

As the fuse box goes, I have a spare and have looked at it pretty thoroughly.
Swapping them out made no difference; but, they both look scroungy so I'm cleaning one of them up already to mount to the new frame. Nothing that goes on the new frame is allowed to look scroungy - cept for the pipes initially lol.

Got the fresh battery box stripped completely last night and put a coat of primer on her. Just put the first coat of black on her and she's a lookin fine.


As for the harness, I've considered routing around the connections inside the
harness and have bought connectors enough to do the job if need be. The way things are looking, I should be back on the electrical tonight.

[argonsagas]

Thanks for the tip on the baggie. A buddy blew the springs to his blinker switch to oblivion so I was prepared for that

As the fuse box goes, I have a spare and have looked at it pretty thoroughly.
Swapping them out made no difference; but, they both look scroungy so I'm cleaning one of them up already to mount to the new frame. Nothing that goes on the new frame is allowed to look scroungy - cept for the pipes initially lol.

Got the fresh battery box stripped completely last night and put a coat of primer on her. Just put the first coat of black on her and she's a lookin fine.


As for the harness, I've considered routing around the connections inside the
harness and have bought connectors enough to do the job if need be. The way things are looking, I should be back on the electrical tonight.

Two things...

Fresh paint (or any paint) is an electrical insulator. Don't forget to provide a very clean ground. I would recommend a second one, as well.

My bike has the usual ground wire, plus I added a second heavy cable that runs down to the frame above the fuse-box.

As to the routing around the harness...forget it. It may be OK for some circuits, but not others as they are unidentifiable with the ohmmeter.

Splices inside the harness are not restricted to the same colour wires.

You may find one colour is spliced into two or more other colour wires inside the harness, (mine are) so if there is actually a problem inside the harness, it is much better for both immediate and long-term effect to address it directly and make any needed repairs.

Don't be afraid to open the harness...there is no biblical incantation to be made before getting into it.

If you decide to do it, just cut carefully and gently into the tape with a VERY sharp knife, and carry on. Start at the fuse box end and you can unwind much of the tape up to the first branch. Cut again, remove the security overwrap, and continue unwinding.

Re-tape from the front of the harness backwards, being careful to keep the branches in the right place to ensure proper fitment. Double back on the wrap at each branch to keep it tight.

You might consider the precaution of taking a photo or two before you make the first cut.

[Anonymous]

Two things...

Fresh paint (or any paint) is an electrical insulator. Don't forget to provide a very clean ground. I would recommend a second one, as well.

My bike has the usual ground wire, plus I added a second heavy cable that runs down to the frame above the fuse-box.

As to the routing around the harness...forget it. It may be OK for some circuits, but not others as they are unidentifiable with the ohmmeter.

Splices inside the harness are not restricted to the same colour wires.

You may find one colour is spliced into two or more other colour wires inside the harness, (mine are) so if there is actually a problem inside the harness, it is much better for both immediate and long-term effect to address it directly and make any needed repairs.

Don't be afraid to open the harness...there is no biblical incantation to be made before getting into it.

If you decide to do it, just cut carefully and gently into the tape with a VERY sharp knife, and carry on. Start at the fuse box end and you can unwind much of the tape up to the first branch. Cut again, remove the security overwrap, and continue unwinding.

Re-tape from the front of the harness backwards, being careful to keep the branches in the right place to ensure proper fitment. Double back on the wrap at each branch to keep it tight.

You might consider the precaution of taking a photo or two before you make the first cut.

Definitely not afraid to cut into the harness if need be. Don't want to do it because I know the tedium involved and was just through it on a CBR in the past few days. Been working with a local mechanic friend of mine over the past week and we tore into a CBR that was getting no power to instruments. Pushing the start button brought up the headlamp and the right blinker circuit. Problem is solved and the bike is now running. But it took both of us. Though I did advise the owner to part it out and sell it on Ebay lol.

I was looking hard at grounding issues when I cleaned the battery box. And the dremel is my best friend right now. Quick easy and clean joints in seconds - made to order ground points. I like it. Now I just have to figure out where to put those "Blue Sun" logos on each side of the box..

As for taking photos of the harness, I've done one better. I have the old harness in a box just for that purpose. And in the event I decide to rewire from scratch (God forbid), I'll have it as a reference. But, I may take some pics too just to be safe lol. Will keep it in mind.

Well, I'm off to bed. My day off today is going to be busy. Interview today, plus working with the mechanic again today, helping brother move And will be working on the bike till late. Something tells me I'll regret having a day off lol

[Anonymous]

Found the problem with the starter ignition system today I do believe.

Started with the yellow/green wire coming off the solonoid to the ignition - traced through the starter switch. There was no power going through the cutoff switch or the start button. Traced that back to the fuse panel. There was power across the fuse box but, at the junction where the fuse box connects to the harness there was no power going into the orange/white line
on the other side of the connection. I managed to get a brief connection
minutes ago and the starter rolled for a moment; but, the connection is too
tenative to stay alive; so, when I get home tonight, that will be the single
focus of my efforts until it is cleaned up and functional.

Thanks for all the help guys. Much appreciated. After tonight, if all goes well, I can start thinking about the engine and carbs, which is where I'm ready to be.