Electrical short? 1981 GS450

[jfsebastian]

Hi everybody
Pls help me here. Bought the bike a month or so ago, with no battery.
Got the right battery and was just plugging it in and as soon as I connected ground (-) to the battery, it started to spark and the ground wire got hot.

What the h.ll is going on???

Pls pls help a desperate man.

Thanks
JF

 

[Guest]

Are you hooking the battery in properly?
Take out the main fuse and then put in the battery and see if it still gets hot. Hopefully it's something simple like the starter solenoid being shorted or even the starter. Could be a bad ignition switch. Take off the tank and follow the wiring harness to see if it's melted anywhere. Also have a look in the headlight bucket.

 

[jfsebastian]

Thanks mate.
Battery hooked up right. FAT cable to + and the smaller - that is connected to the plate and the frame.
How will I know if the solenoid or starter is shorted???

Have checked all wiring I could see with the tank and seat off, but nothing looking melted or out of order.
Hope this woun?t be a long thread with loads of new questions.

 

[jfsebastian]

Tested r/r

Tested r/r

Tested the R/R withh the ohm-meter, and the result are as follows.
Red to blue/white 410
Red to Yellow 454
Red to Green/white 425
Red to ground Black 1012

Is it fried?

JF

 

[SPARKSS]

Hi everybody
Pls help me here. Bought the bike a month or so ago, with no battery.
Got the right battery and was just plugging it in and as soon as I connected ground (-) to the battery, it started to spark and the ground wire got hot.

What the h.ll is going on???

Pls pls help a desperate man.

Thanks
JF

Howdy JF. Are all fuses installed and intact (not blown)? Is there a single negative wire connected directly to your battery terminal or 2? If 2, was only one hot? You seemed to indicate that the postive wire was larger than (the) negative (one). If you have just one negative wire going from battery to frame then it should be at least the same size as the largest postive wire (was this modified perhaps and needs correction)? At any rate, without the key on, merely installing a battery shouldn't cause a current drain so this is the way I'd proceed - disconnect the battery wire from the starter solenoid and try reconnecting the battery......did you lose your heavy current drain? If not, remove ALL fuses and retry......if you lost your current drain now, then re-install one at a time to isolate which circuit is staying active.

This is real basic divide-and-conquer troubleshooting........merely follow positive leads from the battery to where they divide and then remove each leg out from that junction to see where the short exists (by noting where it disappears when removed). Look carefully while visually inspecting to see whether there are positive side wires pinched (and grounded) by brackets and structure or are chafed bare and touching similar (grounded frame components).

As it sounds as if you're seeing significant current (evident by that ground wire heating) then one good culprit (as others have noted) is the starter, heavy current, circuit. either with a short to ground; a stuck in solenoid switch with a seized starter. Does the engine roll over easily (test by rotating the crankshaft itself or merely select high gear and rotate the rear wheel).

 

[BassCliff]

Welcome to "Cooking With Electrons"

Welcome to "Cooking With Electrons"

Hi Mr. jfsebastian,

I've gone back through your previous posts and I can't see where I've given you a proper welcome. My apologies.

Please click here for your mega-welcome, chock full of suggestions, tips, links to vendors and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. You'll find lots of GS lovin' around here. Don't forget, we like pictures. Not you, your bike!

You may want to check and clean every electrical connection and ground on your entire wiring harness, head light bucket to tail light. Check near the bottom of this page on my website for some tips.


Thank you for your indulgence,

BassCliff

 

[SqDancerLynn1]

I would disconnect the regulator/ rectifier then try hooking up the battery

 

[Steve]

Thanks mate.
Battery hooked up right. FAT cable to + and the smaller - that is connected to the plate and the frame.

This almost sounds like the large wire that goes to the starter solenoid and a smaller wire that goes to the fuse box. :-k

Trace the wires to see where they go. You can't always trust the color on these wires. If the wire had gone bad before, who knows what the previous owner might have installed in its place.

If you can't trace the wire directly because it disappears into the harness, just connect the large wire to the battery + terminal and use a test light or a meter to see if you also have power on the smaller wire. If so, it might be the wire that feeds the fuse box and also needs to be connected to the + terminal, not the - terminal.

Are you sure you have proper ground wires connected to the battery's - terminal?

.

 

[jfsebastian]

Pics

Pics

Hi guys.
I?m moved by the way you guys try to help me out here. Thanks.
I?ll post some pics so you can see what I?m talking about.
The FAT yellow cable goes down and connects to the engine (see pic from underneith), the 1 fuse I have is blue, marked 25 and is ok.
The thin ONE cable that got hot is connected to the plate.
I sure hope I didn?t connect - to +, then I?d feel extremely moronic

 

[jfsebastian]

More pics

More pics

One more from underneith.

 

[SPARKSS]

Hi guys.
I?m moved by the way you guys try to help me out here. Thanks.
I?ll post some pics so you can see what I?m talking about.
The FAT yellow cable goes down and connects to the engine (see pic from underneith), the 1 fuse I have is blue, marked 25 and is ok.
The thin ONE cable that got hot is connected to the plate.
I sure hope I didn?t connect - to +, then I?d feel extremely moronic

Well, unless I'm missing something in the translation and pictures, you've got both sides of your battery connected to ground! The heat will be surely in the smaller of the 2, the one connected to the "plate"

That "fat yellow" cable.......appears to be, from your pics and description, a negative lead, AS IS ANY OTHER LEAD CONNECTED TO CHASSIS. Put them both on the negative post of the battery and find the correct wire(s) for the postive side. I apologize if I've misread this as it seems so darn basic.

Gord

 

[jfsebastian]

Thanks Gord
What the f...!!!
2 negative to ground? And yes, the thinner one (left to plate) got hot.
Where is the positive then?
From where does yours go?

This is driving me nuts.

Thanks for helping out guys.

JF

 

[doctorgonzo]

Thanks Gord
What the f...!!!
2 negative to ground? And yes, the thinner one (left to plate) got hot.
Where is the positive then?
From where does yours go?

This is driving me nuts.

Thanks for helping out guys.

JF

Positive goes to the starter relay, at least on mine.

 

[bmac]

wires

wires

Dr Gonzo is right. You have 2 ground wires that are there. One goes to the engine chassis and the is frame source all negatives. 1 new lead you will have to install (fabricate) will be to the starter relay (positive) bmac

 

[jfsebastian]

Well, according to the wiring diagram in the Haynes manual, it should go to the ignition switch, via the fuse and then to the ICU.

Could there be one wire missing from the red into the battery box via the hole below the R/R?
The pic shows the left side of the bike.

JF

 

[Matchless]

Well, according to the wiring diagram in the Haynes manual, it should go to the ignition switch, via the fuse and then to the ICU.

Could there be one wire missing from the red into the battery box via the hole below the R/R?
The pic shows the left side of the bike.

JF

The bottom of the last picture shows the starter solenoid. It will have two heavy wires on it one goes to the battery postive and the other will go to the starter motor.

 

[jfsebastian]

Bingo

Bingo

Thanks Matchless

I am missing that cable all together.
Will make one tomorrow.
Problem solved.
Quite tricky when I?ve never seen the bike with the battery mounted.
Fingers crossed that this was the only electrical problem( yeah right).

Thanks everyone that helped out.

JF

 

[doctorgonzo]

The bottom of the last picture shows the starter solenoid. It will have two heavy wires on it one goes to the battery postive and the other will go to the starter motor.

And I think a third smaller one goes into the wiring harness.

 

[jfsebastian]

Thanks doctorgonzo
That seems to be right. The small one goes to the fuse and into the harness.
Will buy a foot long 12 gauge tomorrow.

JF

 

[SPARKSS]

Thanks Matchless

I am missing that cable all together.
Will make one tomorrow.
Problem solved.
Quite tricky when I?ve never seen the bike with the battery mounted.
Fingers crossed that this was the only electrical problem( yeah right).

Thanks everyone that helped out.

JF

If I was resurrecting that bike I'd be cleaning up a bunch of connections. Just the ones shown in your fine pics are in grim shape (grounds for example....and, if that flying-bolted connection in the white wires is positive (especially) then you'll want to insulate it or if it's a ground side junction at least grease it after ensuring it's clean and well connected. Based also on the general rust and corrosion shown, you could very well have other issues so just take it slowly........clean and repair anything obvious (don't be afraid to enlist some knowledgeable help in your area).......and don't give up and you'll have a good bike.

Gord