What are these wires? '85 K100RS

[NOJUGS]

Hey World, Just bought another bike, 1985 K100RS. I'm taking it apart to see what's there and every time I use air to blow off the top of the motor I find seeds all over the floor. Finally got to the cover under the air box and I guess there was a family of mice living in there at one time. They're long gone now but what a mess!

Anyway my stumper question is: What are the two wires I found, unterminated, under the cover, on the top of the motor? Both wires have a flat female spade terminal on the end, one wire has a male terminal plugged into it, looks like it attaches to a 4mm stud. One wire is brown, I think I have that one figured out, the other wire is Violet/Green, both are about 20 Ga. wires. The terminals are uninsulated and just laying on top of the crank case. They come out of the same trunk of the wiring harness as the coolant sensor.

My guess is that they are for optional equipment not installed on this bike, but I would like to know for sure before I put it all back together.

NOJUGS

[SugarHillCTD]

First of all, WELCOME. Great people and good info here.

Brown wire insulation indicates ground. The coolant sensor should have 2 violet/green wires connected to it (experts here please correct this if I'm wrong)

Here is a link to a K100 colored wiring diagram. Save it and use an image program to enlarge it.
http://smithduck.home.comcast.net/~smithduck/bmw/kwiring/Early%20K75%20K100/K100_Early_Wiring_Diagram.jpeg

Good luck!

[cjack]

Anyway my stumper question is: What are the two wires I found, unterminated, under the cover, on the top of the motor? Both wires have a flat female spade terminal on the end, one wire has a male terminal plugged into it, looks like it attaches to a 4mm stud. One wire is brown, I think I have that one figured out, the other wire is Violet/Green, both are about 20 Ga. wires. The terminals are uninsulated and just laying on top of the crank case. They come out of the same trunk of the wiring harness as the coolant sensor.

My guess is that they are for optional equipment not installed on this bike, but I would like to know for sure before I put it all back together.

NOJUGS

That color, Vi/Gn is the same color as the temp sensor...

[NOJUGS]

I just joined the club yesterday and this was my first ever post on a forum. What a nice surprise!

Thanks for the great wiring diagram. I have a Clymer Manual but I've seen some info that says this is not a reliable source for wiring info. I also got the original owners manual which has a wiring diagram, all I need is a microscope to be able to read it.

I'll check the coolant sensor more thoroughly but I believe it has all the wires attached and is working properly.

The temp sensor also has both wires attached and appears to be working properly.

I saw another sensor on the wiring diagram with the same color wires, a pressure differential sensor, which I think is part of the fuel injection system, but I couldn't find any information about where it is physically located on the bike.

[lostboy]

These are probably the wires for a vacuum switch, which, when sensed for a period of time (my memory says 5 seconds) by the ignition control unit, would advance the tiiming by 12 degrees for better gas mileage. Most of these were disconnected when the throttle cable recall was performed. The best solution is simply to cut these wires. This switch was bolted to the back of the throttle body assembly and connected to the the #1 throttle body with a short piece of vacuum line.

[cjack]

I had forgotten about that vacuum advance. Seems like it was normally advanced 6 degrees and the vacuum did another 6. I don't remember why it was removed but the '86 and up didn't have it.

[NOJUGS]

lostboy and cjack - I'm still digging into what the wires were for, I'll check out your info. The bike was running fine without them connected so it's more curiosity than anything else.

For all who replied and may be interested in my saga - this 1985 K100RS has been sitting for about 5 years, 60k miles, overall decent shape, won't start, runs momentarily with a shot of starting fluid.

I pulled the tank and looked inside - yuck. The vibration damper has turned to goop, I'm wearing rubber gloves as I type this because I can't find anything to get the black goo off my hands! New pump kit coming but still trying to figure out how to clean out all the old muck and get it off my hands. :scratch

Read lots of posts about this issue but didn't find any mention of a good solvent for the degraded rubber damper material. Acetone dissolves it very well but I'm looking for something less aggressive to use inside the tank.

Still hoping to be riding by the end of the month - Ride safe

[Kayseventyfive]

John, that wiring diagram is a beaut.

Would you have one (or a link) for a K75?

[mieczkow]

You can get these very nice laminated wiring guides on e-bay for $20 - I bought one for my K75S and it is really nice. It includes a diagram for the ABS system as well if your bike has that feature.

[bimmernut2]

Hi Guys : I too am new to the site and have my 2nd k100 ,this one has a running problem. after I traded for this bike I found that whoever installed the new fuel pump just thru it in the tank . I orderd all the nessasry parts, pump holder ,filter nuts and washers ect. the bike ran rough, very cold natured. even then would not idle. I installed new coils and fixed the surging and it still would not idle and still cold natured. I replace temp sensor and cured the cold running . could not believe the way it started and idled. but then it created another problem. now when you roll on the throttle it bogs down for a second.( really a pain when shifting thru the gears) seems to be running rich for a few seconds. any Ideas?
PS on a side note this is an 89 rs but seems to have twice the power of the 1100lt I had before. thanks for any info

[deilenberger]

FOLKS:

ModNagON/

I'm adding the year/model of your bike to the thread title. Please consider doing this yourself when starting a thread - it helps attract people who may have something useful to offer to your thread.

ModNagOFF/

[deilenberger]

Hi Guys : I too am new to the site and have my 2nd k100 ,this one has a running problem. after I traded for this bike I found that whoever installed the new fuel pump just thru it in the tank . I orderd all the nessasry parts, pump holder ,filter nuts and washers ect. the bike ran rough, very cold natured. even then would not idle. I installed new coils and fixed the surging and it still would not idle and still cold natured. I replace temp sensor and cured the cold running . could not believe the way it started and idled. but then it created another problem. now when you roll on the throttle it bogs down for a second.( really a pain when shifting thru the gears) seems to be running rich for a few seconds. any Ideas?
PS on a side note this is an 89 rs but seems to have twice the power of the 1100lt I had before. thanks for any info

Bimmernut - this posting would be much better served by being in a thread of it's own (with the YEAR/MODEL in the thread title..) If you go back up one step to Garage/Flying Brick K Bikes - there is a button for "New Thread". PLEASE do put the year/model in the thread title - that saves me the trouble of having to add it.

I'd suggest starting a new thread.

Thanks! And welcome to the forums!