one coil hot other coil not getting ground

[Guest]

Ok so I have a problem, My bike has been hard to start when cold for a while. It usually got going and ran perfectly fine. Last week my wife and I were about to go for a ride and it wouldn't fire. Finally 2 cylinders fired up 2-3 and bike ran like poo and had no power so that ride got cancelled.

Left coil not getting power on the ground wire which is white. I have power on all 3 other wires. I can get cylinders 1-4 to spark if I take a wire from the black wire on the right coil and jump it to the left coil.

I have checked all the connections and there wasn't very much corrosion on any of them other then some rust on the tank and seat. I cleaned off the ground under the battery as well as the bolts for the coil.

I printed and went through the tech guide and my guess is that the wire may have some problem somewhere along the way but that doesn't explain the hot coil?

any suggestions.

[sangheraent]

I swear I was part of this forum before im not sure what happened. I use it a ton.

[chef1366]

It's either a bad crank trigger or a broken wire.

[sangheraent]

I think so too.

Is - terminal on the coil a ground? I know the red/orange wires come from the kill switch, but Im not sure where the - wires come from one side is black it works fine the other is white it doesn't work at all.

I am wondering If I can by pass it some how to test the wire. is the - terminal wire the line from the pickup coil? if so then i have to test the pick up coil as well.

[mmattockx]

I think so too.

Is - terminal on the coil a ground? I know the red/orange wires come from the kill switch, but Im not sure where the - wires come from one side is black it works fine the other is white it doesn't work at all.

I am wondering If I can by pass it some how to test the wire. is the - terminal wire the line from the pickup coil? if so then i have to test the pick up coil as well.

What bike do you have? The coil negative terminal goes to the ignitor on the electronic ignition bikes. At least it does on my 1100E. Orange/White (again, on my 1100E) are +12V from the battery and go to the positive coil terminal. The other two are switched to ground through the ignitor.


Mark

[Brendan W]

The coil plugs can look ok but the wires can be corroded in the terminals.

[Steve]

any suggestions.

First suggestion is to tell us what bike we are discussing.

Left coil not getting power on the ground wire which is white. I have power on all 3 other wires.

"Not getting power on the ground wire" is actually quite NORMAL and EXPECTED.

And what are the "3 other wires"? Every coil I have seen DOES have 4 wires, but one supplies power, one goes to the points (mechanical or electronic), two go to the spark plugs. The closest thing to a "ground" wire is the one that goes to the points.

.

[sangheraent]

Sorry my bike is an 81 GS650G. 35000 kms on it. Sat for 20 years ran great first 2-3 months after valve/carb work.

I have power on the 2-3 could spark everything is good. The left coil is getting power on the hot side when i use the bikes ground it shows power to the coil but it will not show power when i use the - terminal for the ground. The other coil does that fine.

I can get coil 1-4 running if i jump it from the - terminal on the 2-r coil.

[Brendan W]

Where are you measuring the voltages ?

[chef1366]

So you're saying that if you switch the ground wires (not the OW) and you get the other coil to spark?

[jdvorchak]

Let me try to explain how coils work. First you have 12v on the + primary side of the coil. That energizes the coil when the - side of the coil is grounded. That is the normal condition with the bike not running, ignition on. Now to get a spark you have to remove/disconnect the ground via points opening or ignition (CDI) box switching it off of ground at the proper time. The energized coil "field" collapses and generates a spark on the secondary or high tension coil firing the spark plug.

So that narrows down your problem to one of 3 things to check. First disconnect the coil primary wires and measure the resistance of the primary coil. Should be 3 to 5 ohms. If you get below 2.5 ohms or you get more than 5 ohms the coil is bad. Usually they will read very high resistance like 2k ohm or open (infinity) when bad.

Now if the primary resistance is between 3 and 5 ohms then check the wiring to the ignitor. If connector is clean that is usually not your problem.

So that leads us to the pulser or signal generator. Look in the Factory Service Manual for your bike and use the resistance check. Typically 250 to 350 ohms but check for your model for the value and which wires to check. If that checks good then your Ignitor box (CDI) is bad.

[sangheraent]

Let me try to explain how coils work. First you have 12v on the + primary side of the coil. That energizes the coil when the - side of the coil is grounded. That is the normal condition with the bike not running, ignition on. Now to get a spark you have to remove/disconnect the ground via points opening or ignition (CDI) box switching it off of ground at the proper time. The energized coil "field" collapses and generates a spark on the secondary or high tension coil firing the spark plug.

So that narrows down your problem to one of 3 things to check. First disconnect the coil primary wires and measure the resistance of the primary coil. Should be 3 to 5 ohms. If you get below 2.5 ohms or you get more than 5 ohms the coil is bad. Usually they will read very high resistance like 2k ohm or open (infinity) when bad.

Now if the primary resistance is between 3 and 5 ohms then check the wiring to the ignitor. If connector is clean that is usually not your problem.

So that leads us to the pulser or signal generator. Look in the Factory Service Manual for your bike and use the resistance check. Typically 250 to 350 ohms but check for your model for the value and which wires to check. If that checks good then your Ignitor box (CDI) is bad.

Sorry for the huge delay got busy with work and had to put the bike on the back burner.

I tested all my coils by switching them out back and forth. I have 4 coils (2 on bike 2 spare) and they all work when connected on "the good side". The pulser says 150 ohms I think this is my problem. I checked the switch on the handle bars and there was almost no corrosion in there. So I am going to try a new pulsar and see where that takes me.

[jdvorchak]

Sorry for the huge delay got busy with work and had to put the bike on the back burner.

I tested all my coils by switching them out back and forth. I have 4 coils (2 on bike 2 spare) and they all work when connected on "the good side". The pulser says 150 ohms I think this is my problem. I checked the switch on the handle bars and there was almost no corrosion in there. So I am going to try a new pulsar and see where that takes me.

What does the FSM say the value should be for your bike?

[60ratrod]

so what you need to do is the ignitor test, which is outlined in the FSM, this is taking into the equation that you have the factory ignitor, and not an aftermarket unit like the dynatek ds unit. the factory ignitor is located on the same plate as your r/r underneath your airbox.

-what you need to do is pull the plugs from cylinders 1 & 2, then locate the connector with the blue & green wires found behind the left side cover by the battery.
-disconnect it and figure out which side runs to the ignitor, leave the ignition key off the whole time you are doing this test.
-once you've found out which one goes to the ignitor, set your meter to the continuity/diode setting.
-connect the black lead from the meter to the blue wire, then connect the red lead from the meter to the green wire.
-once you connect both leads, plug #1 should spark. disconnect the red lead and plug #2 should spark.

if only one plug sparks, then your ignitor has gone bad, which is getting more and more common with the 650s. you have 3 options if it has the factory ignition: 1) buy one from a member here or from ebay, which is a gamble if it works or not. 2) build a diy ignitor. these work. I built one for mine and worked well until one of the hei modules burned out on me. 3) buy an aftermarket ignition kit like the dynatec ds 3-2.