coil prob

[Anonymous]

I have a 1981 GS 850 G and it dosint fire on #3 and i can hear arcing like the wires are bad. So I found a set of coils on Ebay and bought them.
Now i am confused I recived them and looking at the wires thay are marked 1&2 on one coil and 3&4 on the other. My exsisting coils are marked 1&4 on one and 2&3 on the other also my exzisting coils have the orange and white wire conecting to the rear of the coil and the yellow and black wire is attached to the front of one coil and the white wire to the other. On the coils I recived on Ebay they have positive and negitive posts on the rear of the coil. With that said can the coils I bought work on my bike with some wiring modification? Also what wirers go to the positive and negitive.

orange and white---------------- starter button
Yellow and black----------------- ignitor unit
White-------------ignitor unit

If anyone can shed some light on this subject please let me know thanks

[SqDancerLynn1]

Forget about how the coils are marked run the 12v to the coil + and route the wires 1&4 2&3 as original

[Anonymous]

coils

make sure one coil goes to 1&4 and the other 2&3 and make sure the positive connection and grounds are all correct

[Anonymous]

Re: coils

eg if it says 3 and 4 put that coil to 3 and 4 and make sure the 3 and 4 trigger wire are correctly postioned on the coil same goes for the other...and as long as each trigger wire for each specific cylinder is correct it will run right

Sorry, that's incorrect. SqDancerLynn1 has it right. Cylinders 1&4 both reach TDC (one cylinder on the intake cycle, one on the exhaust cycle) when 2&3 reach BDC, so 1&4 fire together and 2&3 fire together. Each coil has just one secondary output, but instead of one lead connecting to ground like in an automotive coil, both leads are "hot," essentially completing the electrical circuit through both spark plugs. Since one cylinder of the pair will always be on the exhaust cycle when the coil "sparks," there is no mixture to ignite.

Hope that clears things up.

kbj

[Anonymous]

thats exactly what i meant.....one thing i got mixed up on i thaught the particular coils had 2 triggers on them and had each cylinder fire individually....BUt these engines fire two at a time...food for thaught.. i didnt explain it well since 2 cylinders are triggered at a time eg 1&4 one coil has to be connected to these and for 2&3 another and the grounds for the triggers have to be on the right coil for it to run....the only reason the numbers on the coil are different is because its probably from a different bike. If you ran the numbers on the wires to the number of the cylinders it would not work. Not on your bike neways...

[Anonymous]

The haness should have 1 wire that goes to both (-).

The harness should have one wire that is split with two connectors on it. This is the (-) for both coils.

The two pos wires are for 1,4 and 2,3.
Which ever pos wire color code from the harness goes to 1,4 hook that wire to the (+) of one coil and make sure that coil has wires labeled 1,4.

[Anonymous]

Re: The haness should have 1 wire that goes to both (-).

The harness should have one wire that is split with two connectors on it. This is the (-) for both coils.

The two pos wires are for 1,4 and 2,3.
Which ever pos wire color code from the harness goes to 1,4 hook that wire to the (+) of one coil and make sure that coil has wires labeled 1,4.

NO! The + side (orange/white) comes from a double connector in the wiring harness!!!!
The - leads (black/white for 2&3 and white for 1&4) go to the points or the ignitor!!

[Anonymous]

On my 850.

I don't remember the color codes but I hooked up the new coils just the same way as the old ones came off.

The (-) harness lead for both coils was a comon wire that went to both coils. The (+) leads were separate and had different color codes, one for each coil.

[Anonymous]

Re: On my 850.

I don't remember the color codes but I hooked up the new coils just the same way as the old ones came off.

The (-) harness lead for both coils was a comon wire that went to both coils. The (+) leads were separate and had different color codes, one for each coil.

I don't know if it makes any difference, but normally the (-) side goes to the ignition points (or like in this case, the ignitor unit), switching the coil to ground. There are two wires, with different colors.
The (+) side of both coils connects to the battery (through the ignition lock, of course). So normally this would be the common wire.
This is the normal setup for cars and bikes.

All I can think of, is that if you connect the wires differently, you would get a negative pulse at the spark plugs instead of a positive, when the points open.
Perhaps I'm wrong; it might not make any difference at all. :roll: