Still Baffled!!!

[kimrpaige]

86 K100RT wiring harness

Hello,
I am new to the K bikes and new to this forum. I have a 86 K100 that was involved in a fire, and trying to get it back on the road after the PO replaced the relay box and wiring. I seem to be missing a connector, or my eyes are getting really bad. I plugged the ign switch connector where the PO had the fuel pump or tank connector plugged into, as the frame plug had the same color of wires as the switch harness did, now I seem not to have a place to plug in the tank/pump. Can anyone tell me where the plug is and what color of wires it has. My manual shows the plug attached to the relay box. I do not dare putting power to the bike not knowing if all is correctly connected or not. My tank connector is oblong half rounded, 5 pin like a couple of others like the ign switch. Any wiring experts out there or do I have to trailer it to the local BMW shop??? Kim

 

[kimrpaige]

Hello again,
I posted a thread early this am about my wiring harness, or lack there of. I installed all the fuses, put the charger on it and all is well except I do not have a plug for my fuel tank!!!! I am baffled, Did they have different plugs for different models?? My old burned up harness has a plug but the replacement (used) does not, nor any that even looks like one. I am not sure what year or model the harness is from as the PO installed it. I guess I will have to cut my old plug and splice it in. Any suggestions?? My tank has 4 wires: yellow, white, green, and blue. The old harness plug is: yellow, white, green/white, and brown. Kim

 

[deilenberger]

I think without knowing what harness you installed (or the former owner installed) and what bike this is on - this question is unanswerable.

Different year K bikes used different harnesses - different model K bikes used different harnesses.

Fer'instance - the '85 (and '83-84 in Europe) K bike had a fuel-pump/fuel-gauge connector at the front left corner of the tank. It was a round plug in connector that went right into the bottom of the tank. Later K bikes used a semi-oval connector that connected to a pig-tail connector coming off the right rear corner of the tank.

Obviously - if your have a mismatch of harness/bike-year you won't have the correct connectors. You also stand a good chance of blowing up your instrument cluster if you try splicing something in.

We need a lot more information from you to form an intelligent answer. Just saying the connector doesn't exist makes me think you have some sort of mismatch.

What year/model is the bike?
What year/model did the replacement harness come off of?

UPDATE - I see you are clueless as to the harness the PO installed. I'd suggest contacting BeemerBoneYard and finding out what a replacement harness that is matched to your year/model will cost you. That's the only reliable way of knowing everything will work. Hope you bought the bike cheap..

 

[BUDDINGGEEZER]

Still Baffled!!!

Hello again,
I posted a thread early this am about my wiring harness, or lack there of. I installed all the fuses, put the charger on it and all is well except I do not have a plug for my fuel tank!!!! I am baffled, Did they have different plugs for different models?? My old burned up harness has a plug but the replacement (used) does not, nor any that even looks like one. I am not sure what year or model the harness is from as the PO installed it. I guess I will have to cut my old plug and splice it in. Any suggestions?? My tank has 4 wires: yellow, white, green, and blue. The old harness plug is: yellow, white, green/white, and brown. Kim

According to the Clymer diagram the frame plug is wired
Brown=ground;
Green-White/ power from #6 fuse(changes to green on the plug connected to tank 87 models); this is the power to the fuel level sensor which supplies the power to the fuel pump.
Yellow= fuel guage;
White= low fuel light.

The #6 fuse is powered by the fuel injection relay. These bikes appear to not have a fuel pump relay as do the later models.

I would assume the blue wire on your tank plug is ground(maybe the brown has faded).

The ignition switch is also 4 wires Brown/Green/Blue-Green/Gray. They should not be the same as the fuel tank plug, as you stated in your earlier post.

Look for a plug with the proper color wires that connects to your tank plug. Worse case trace the wire from #6 fuse and wire to Green. If you don't have a fuel guage don't worry about the yellow.

The later models appear to have a 5 wire harness and use a fuel pump relay/2 Green-white wires. Maybe you have a later model harness.

I reserve the right to be wrong, but I don't think I am????? I have found Clymer to be wrong on occasion.

Ralph Sims

 

[kimrpaige]

Ralph,
I am quite sure you are right. I know by the chart in the owners manual and my old harness and my tank harness that you are right. I am going to wire in my old plug to make it work, not a big deal just two wires or four if I want the low fuel lite. I just don't understand why I can't find the plug. It had to have had one!!! I have a 86 K100RT, and yes it has the oblong with one flat side connector on the right rear of the tank. Everything works when I turn the key on, cluster, turn signals, lights , clock, gear pos, etc. Now can I assume the pump works like a car? Fuse 6 only hot for a couple of seconds when the key on to prime the rail, then on constant when cranking and running? Yes I got it cheap and it is in good condition, just needs paint as the other donor bike was used to replace all the burned up fiberglass. 39K on the clock. Had a 73 R75 back in early 80's and loved it. This is my first K. I should try to starrt this week or next, waiting for exhaust gaskets for the headers to arrive. Thanks to all who have replied!!

 

[deilenberger]

Ralph,
I have a 86 K100RT, and yes it has the oblong with one flat side connector on the right rear of the tank.

OK - then I'd assume someone put on an earlier harness.

Look in the area front left corner of the tank. Look for a round 4 pin connector (female). Two leads are fuel pump power (Ground and +)

The other two were for the level indicator - do NOT CONNECT THESE to the sender in your '86 tank without comparing the wiring diagram for the 85 bike harness to an 86 K100 harness. If things don't match up going into the instrument cluster - there is an excellent chance you'll destroy the cluster.

Also - please use a few paragraph breaks when you post. It makes it much easier to read, understand and reply to your message. Thanks..

 

[deilenberger]

Mod note - merged the two threads into one. Makes it easier to keep track of things.

 

[kimrpaige]

Thanks for the merge.

I checked my harness again last night and no there is no plug for the tank, Got me??? Any way I am going to wire it up and not use the low fuel light. I did check my pump and my spare pump, both are frozen, so will try and free if not I will add a replacement like on the IBMW site. Thanks to all, and will keep you posted as when I get her running again after who knows how many years! Kim

 

[kimrpaige]

I found it!!!!!!! I am no longer baffled, The PO had it stuffed inside the coil cover. I was installing my plugs and wanted to make sure I had the wire on right so I removed the coil cover and presto my fuel tank plug!! Thats again to all that replied. Almost ready to fire him up!! I am sooo excited!!