Help please!
I'm in the process of installing a temp guage to my 85RS (as well as a voltmeter). I've been able to accumulate all the bits and pieces req'd, (even a new temp motometer, at a good price). I have installed the guages and other wiring except for the sensor wiring. My problem is where to route the wire from the new sensor up to the wiring harness under the tank. I assume it would follow the existing temp sensor wiring and have tried poking a stiff wire leader up into the opening at the oil/water pump, but the wire only goes "in" about 125mm and stops.
Am I on the right track here or what?

yes you are right
from the bottom pass through hole the wiring takes a sharp turn towards the front ....then up through the hall sensor (timing gear) cover
its just a little tricky getting it towards the front ......I guess you are using something like coat hanger wire ? about a foot long ?

put a bend in it of about of about 45 degrees over  2 inches ..about 3 inches from the tip .....also bend the tip over slightly so it folds back on itself  no bigger than about 7mm  ...that might help get it around the corner a little ?

else tie a thread wire to the current sensor wires and pull the whole lot up ...than attach the new and pull the whole lot back down again ......old sparkies trick

good luck !

Thanks for that Charlie.
The thought of using existing wire as a pull thru crossed my mind, but if something went wrong I'd be up the proverbial creek without a paddle!
I'll give your suggestion a crack tomorrow. For now it's time to have a glass of red or two or ...

Glad you asked the question. I'm adding a temp gauge too and from the looks of the installation guide I have from BMW it's is a bit of a pain to route the wire.

Just a thought, but when I did mine I didn't bother running it up along with the Hall Sensor and oil pressure wires. Just ran it up the outside. Will admit it is probably more professional to run it up along with the oil pressure sensor line. But it's not really noticeable unless you know what you're looking at.

hope there are no stones on your roads ....there is a tendency for them to hit all across the front of the motor ...my oil pump assembly needs a repaint every 6 or so months .....hope those cables survive
its all about mechanical protection

I finally gave up trying to route a coat hanger type wire in up around the water pump to route the sensor wire. I noticed a oil leak from the pump and decided to bite the bullet and removed the pump to overhaul it. I could now see where the wire should go and realised that the timing cover must also be removed which is simple to do. 
In hindsight the job could probably done by just removing the timing cover and poking a wire leader up the water pump. 

charlie99 wrote:hope there are no stones on your roads ....there is a tendency for them to hit all across the front of the motor ...my oil pump assembly needs a repaint every 6 or so months .....hope those cables survive
its all about mechanical protection

Agreed. And now knowing there is a better way I will probably make the change after I get through the current restoration project (different bike). But in truth the biggest problem has been vibration causing intermittent contact coupled with wind which has tended to disconnect the wire.

BTW, anyone have experience with powder coating the front plates on a K? I'll take the question over to paint and frame.

yes indeed vibration is a high cause of failure with copper