buying 850 g with probable spark issue

[ron bayless]

its an 81 850 g.he said his friend was riding it around the block and it just quit.it turns over but wont start.I couldnt test it since his battery was down, had been sitting for 5 months.i know on some bikes there are relays for either the sidestand switch,starter, or the sidestand switch or clutch switch themselves can cause no spark.I will be taking the bike from his house to mine day after tomorrow.he had taken the 'ignition " loose to see if that was the problem.What he had done was cut the wires coming from the starter button and killswitch and tried to make the loose ends start the bike.has nothing to do with the ignition system.His starter button though does have a direct connection to the solenoid if i understand the bike wiring correctly.first thing i will do is reconnect the wires he disconnected.Then I will hit starter button with bike in neutral and clutch lever pulled in and see if it starts.if not, look for blown fuse.fuses ok, look at connector down by sidestand switch.Also see if any hot wire disconnect from battery, to main fuse, to r/r, to ign switch.I will also check grounding.Also check for loose or messed up coil wires.What else should i do?

Question; do these bikes have cdi or tci?

 

[Steve]

i know on some bikes there are relays for either the sidestand switch,starter, or the sidestand switch or clutch switch themselves can cause no spark.

The closest that any GS comes to that is the clutch switch that has to be pulled to engage the starter. There are NO devices that will stop the engine except the RUN/STOP switch and the ignition key.

Question; do these bikes have cdi or tci?

They do NOT have "CDI".

Not sure what you mean by "TCI", the only thing I can think of is "Transistor-Controlled Ignition".
If that is what you mean, yes, it's there, that is what we call the "ignitor". "Ignitor" is actually a poor choice of terms for the device, as it does not really "ignite" anything. It's just a box of transistors that takes the place of the points from the earlier bikes.

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[ron bayless]

Yamahas have tci.Dont know what it means either.Ig niter i am familiar with.Doubt its that, it was running and suddenly quit.

 

[rustybronco]

Ron....

http://members.dslextreme.com/users/cbsaunders/gs/Repair_and_Fault_finding_GS1000G_Ignitor.pdf

 

[ron bayless]

Picture of connector

Picture of connector

I tried downloading a picture of the connector only.Will try again.

 

[ron bayless]

dont know where to begin.

dont know where to begin.

I suppose you start trying to pull these bigassed harness out through a space that is too small to pass through, then unplug from the old, fish the new back through, replug back in and hope it all goes to the right places.This has me maxxed out with selfawareness of my inability to do this. IMG_20131003_162654.jpg (67.8 KB)

 

[Redman]

Ignition fuse also powers the starter button-solenoid circuit.

Only interlock on the starter solenoid circuit is the switch on the clutch (1980 and after). Doesn't matter what gear or netural. Doesn't matter about any sidestand swtich (if there is one).

 

[Steve]

The mass of the harness is greatest in the middle, near the battery box.

Pull all of your original harness toward the battery, then locate that part of your new harness and feed it toward the front and rear.

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[ron bayless]

Thanks Steve and Redman.

 

[ron bayless]

Ground wire is toast everywhere I looked.I need wiring 101.Why was it the ground wire was so burned up.I thought it grounded, not conducted electricity. I don't understand flow,please explain.IMG_20131004_115247.jpg (48.1 KB)

 

[JayWB]

Ground wire is toast everywhere I looked.I need wiring 101.Why was it the ground wire was so burned up.I thought it grounded, not conducted electricity. I don't understand flow,please explain.IMG_20131004_115247.jpg (48.1 KB)

Conducting electricity is precisely HOW it grounds.

Electricity always has to return to its source. On a motorcycle the source is either the battery or the rectifier / regulator. You don't really get to decide where the electricity will return to, it needs both, and that is why both have the exact same return path. We call that return path "GROUND".

 

[ron bayless]

Conducting electricity is precisely HOW it grounds.

Electricity always has to return to its source. On a motorcycle the source is either the battery or the rectifier / regulator. You don't really get to decide where the electricity will return to, it needs both, and that is why both have the exact same return path. We call that return path "GROUND".

OK.Then why did the ground wires burn up.If their job is to return the flow, what caused them to overload and burn? I would guess a short ie some broken area in the ground wire touching metal as in the frame. But, I thought that was what you wanted, the ground wire touching the frame.

 

[JayWB]

Technically speaking, ANY point in a wire that is properly connected to the frame (ground) may be also considered to be ground. So if you have a wire that is connected to ground at one end, touching ground with it ANYWHERE along the length of the wire does exactly ....... nothing. It's like touching the wire to itself, or touching ground to ground.

As for why your ground wire burned, it's for the same reason any other wire would burn: an excess of current went through it, it got hot, and it burned. Just being a ground wire doesn't change a thing, it's just like the positive wire. In fact, every electron that goes through the positive wire from your battery has to go back to the battery, through the negative wire. It's exactly the same current.

 

[ron bayless]

Technically speaking, ANY point in a wire that is properly connected to the frame (ground) may be also considered to be ground. So if you have a wire that is connected to ground at one end, touching ground with it ANYWHERE along the length of the wire does exactly ....... nothing. It's like touching the wire to itself, or touching ground to ground.

As for why your ground wire burned, it's for the same reason any other wire would burn: an excess of current went through it, it got hot, and it burned. Just being a ground wire doesn't change a thing, it's just like the positive wire. In fact, every electron that goes through the positive wire from your battery has to go back to the battery, through the negative wire. It's exactly the same current.

That is exactly the kind of explanation I wanted.Thank you.

 

[ron bayless]

Ok, what might be the cause of that happening? An excess of current.

 

[JayWB]

An excess of current is usually because an uncontrolled connection to battery voltage has occurred.

Let's talk about the most basic of circuits, a simple light bulb. You start at the battery positive, which is at 12 volts. There is a wire that goes from the positive terminal to one side of the light bulb, then another wire that goes from the other side of the light bulb to the negative terminal of the battery. As long as the light bulb is good and the battery is charged you have light.

Then, after 30 years of operation and vibration, the two wires rub together and wear the insulation off. Current now goes from the battery positive through the wire until it finds the worn insulation, then it takes the SHORT CUT into the negative wire and returns to the negative terminal of the battery, bypassing the light bulb entirely. This is where we get the term "short".

Unfortunately, aside from just rendering the light inoperative, it also damages the wires. This is because the light bulb was restricting how much current flowed through the wires. Dim lamps allow a little current, brighter lamps allow more current. Headlights allow still more current. A "shorted" circuit allows virtually limitless current, limited only by the resistance of the wires themselves, and that isn't much. So the circuit takes every electron your battery is willing to provide, overloading the wires tremendously, overheating them, and burning them.

It is for this reason that fuses exist. The power (12 volts) has to go through them FIRST.. If a short occurs, the fuse will overheat and melt long before the wires will overheat and burn.

 

[ron bayless]

That is a great explanation.Problem is, my harness melted from the instrument panel to about midway under the tank before I got the battery disconnected, and a fuse never blew.The problem I had defies all logical explanation. The short I understand, why didnt it blow at least the main fuse, I have no explanation for. I also have been contemplating how smart is it to replace a faulty 30 year old harness with another old harness from ebay? New ones cost $157. My used one was $45.I am hoping the replacement harness does not fail. I am also hoping when i remove the old harness something jumps out at me where I can say there was the problem.

 

[Steve]

..., my harness melted from the instrument panel to about midway under the tank before I got the battery disconnected, and a fuse never blew.The problem I had defies all logical explanation.

Well, since it defies "logical" explaination, how about a possible explaination? :-k

Take a look at the fuse. Those glass fuses are available up to 30 amps.

Most of the wires on the bike will melt with 30 amps going through them.

The MAIN fuse should be 15 amps, all the others should be 10 amps.

Too many times, a "previous owner" will install a larger fuse.

.

 

[ron bayless]

Well, since it defies "logical" explaination, how about a possible explaination? :-k

Take a look at the fuse. Those glass fuses are available up to 30 amps.

Most of the wires on the bike will melt with 30 amps going through them.

The MAIN fuse should be 15 amps, all the others should be 10 amps.

Too many times, a "previous owner" will install a larger fuse.

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Good point.I am off in a few days.Thats when I will try and fix it.The PO did a lot of stuff I don't like.

 

[ron bayless]

old harness is fubar.IMG_20131011_104100.jpg (55.2 KB) The old connectors are so melted I had to cut them out.I dont know if i will ever get replacement harness in.Theground wire was creamated, then set others to melting.I cant imagine what happened.