I'm sorting out my newly purchased 86 K100RS.  There are a few electrical and other issues and despite being dormant for a few years, overall it is in good condition.  Under the tank I found a coiled up unconnected ground wire from the upper frame tube grounding point.  It is long enough to certainly reach the headlight area and as the pic shows, there is a factory eyelet on the end.  Any idea where this should go? 
Next one is a light gauge wire coiled around the Motronic lead in cable and goes up to the headlight terminating in a plug (which was unplugged).  What is the function of that wire ?  Thanks

DavidKS wrote: Next one is a light gauge wire coiled around the Motronic lead in cable and goes up to the headlight terminating in a plug (which was unplugged).  What is the function of that wire ?

Your Brick has an LE Jetronic engine management system, David. The Motronic system is in the somewhat later four valve models. Your Brick's engine is a two-valve model.

Does the front master cylinder housing of your Brick have a similar light gauge wire with ring terminal bolted to it somewhere?

Thanks for response and clarification on the Jetronic.  No wires to the MC other than the brake light switch ones.

It's not a factory device.
Probably an aftermarket power supply for casual gadget.

If the ring terminal is 6mm then it bolts to the captive nut on the frame next to the ignition unit. If the ring terminal is 4mm then it bolts to the lower (and almost invisible) screw on the master cylinder mount/perch. The one that's wound around the fuel injection control unit cable looks like a bodge job for a  broken wire. The only way you're going to solve that problem is to open up the headlight and the FICU to see where it has been terminated. My guess? It's a brown (earth) wire.

Thanks Dai   One end of the wire is already attached to the grounding terminal near the ignition control unit.  The other end has an eye measuring at 5.3 MM in diameter.

Thanks JBT  Well I am certainly not a fan of extra stuff being hooked up, especially to the ECU.  So I pulled back the sheath on the Jetronic connector and yes, that thin wire has been added on to the yellow with a bluish tracer ( see pic).  That is terminal 12 of the ECU which looks to be the 12V for the injectors.  I'm curious why someone would tap in there so when I have the front wiring exposed, I can trace where the other end goes.  And yes, it will be removed, not really safe having the very lightly insulated wire traveling that long distance just waiting to short out and taking out the ECU with it.

That light gauge wire goes into the instrument cluster and looks to be the feed for the "Fuel Plus" add on the bike has.  I only found a bit of info via google, can anyone tell me what it's function was.  Thanks

DavidKS wrote:I only found a bit of info via google, can anyone tell me what it's function was.  Thanks

Did you find this bit, David?

Fuel Plus Manual:
http://dws.epizy.com/ktech/Fuel.Plus.Computer.Manual.pdf

Thanks so much duck,.  I bet it would have been difficult to figure it out by trial and error.

Many thanks Laitch, more info to digest, just what I like !

I have a Fuel Plus unit on my K100LT and I like it. It fits into the original dash clock spot. It shows lots of info including real-time fuel consumption and distance remaining to empty. It is a cool little gadget that some very clever person put a huge amount of work into.