Coil wiring

[norisan]

I have a '94 K75S which starts instantly, idles and runs smoothly but seems to have no ignition advance - down on power, heats up and uses a lot of gas. Looking at the coils it may be missing a wire. It has two wires to two coils and three wires to the third, plus a short ground wire to the frame. This bike is new to me but if memory serves me right my previous k75 also had a (brown?) wire in the harness that I believe went to ground? Can anyone confirm this and indicate where that wire connects to and from? Thanks.

[norisan]

 There must have been some shorting between wires in the harness as it appears the previous owner cut the brown ground wire  to the coil out of the harness, then ran a ground directly from the coils to the frame. I'm assuming sometime during this the ignition module was damaged so that there was no longer any advance. I've reconnected a ground into the harness and as soon a my Ebay ignition module arrives I'm hoping the problem will be solved, I'll post the result.

[Scott_]

Each coil should have a wire(green/yellow), that will be +12v power from the kill switch.
Each coil should have a ground wire(brown) for the secondary(spark side), high voltage circuit.
Coil #1 will have 2 black/blue wires. One will be from the ignition module, the other goes to the inst cluster for the tach.
Coil #2 will have a black/red, and coil #3 will have black/green, both of those then also go to the ignition module.

The low voltage circuit of the coils(including timing advance) is all controlled by the ignition module.
If the brown wire from the coils is broken, you should have no spark, or very weak spark at the plugs. This would have no effect on spark timing specifically. If the harness wiring is bad or questionable, I'd connect the coil brown wire direct to the engine block.

[norisan]

The Previous owner had connected a ground directly from the coils to the frame so it was running fine, without advance. I've repaired the wiring harness and connected a new ground wire. I opened up the Ignition control module and it has a definite burnt smell. I will swap in a new module sometime this week and hope that will solve the no advance problem.

[norisan]

Problem solved - as suspected it was a bad ignition control module.