ABS problem

[kmark]

I am new to this forum so please bear with me. I have a 1994 K1100rs, with ABS. I believe it's the ABS II. I bought the bike years ago always had problems getting the ABS to work. I have switched out the servo pump 3 times, had the thing work for a short while several years ago. I have not had the bike on the road for about the last three years, now I am trying to get it back together. I started it today and it runs good. Shut it off and smoke starts coming out from under the tank. Long story short, the brake line from the abs pump to the front master cylinder gets red hot to the point that it boiled the brakefluid and blew out the sight glass on the master cylinder. I have never seen anything like it. I had the bike running about three times this past week, with just short trips down the driveway to see if the ABS issues were worked out. The ABS lights were blinking simultaneously, but if I drive away, they start blinking alternately. I didn't get a chance to check for codes since the thing caught fire today. Has anybody ever seen or heard of anything like this? Thanks

[Scott_]

One thing I would check is the gaps at the wheel sensors.

Front .50-.55 mm(.0197-.0217in)
Rear .60-.65 mm(.0236-.0256in)

I can't think of anything that would make the brake line red-hot except some battery current flow from a short circuit, I suppose it could be possible that there could be a short in the battery lead that is connected in the pump terminal box. How is your battery holding up- starting, etc...

[kmark]

Battery seems to be fine. How about at the pump terminal box, do you think I could have mixed up some wires there?

[Scott_]

There will be 4 wires going into the box. Large ga red + power wire, a large ga - ground wire, and 2 smaller ga control wires.
I'm thinking that the wire terminal ring sizes are different so that you can't mix up the + and - leads.



I suppose it's possible there could be a breakdown of an insulating barrier internal to the modulator.
The only way to really isolate it would be to trace the red power wire from the controller to the relay box(under the gas tank) and disconnect it. 
If you no longer have the 'heating effect' on the brake tube, then at least we know where the current is potentially could be coming from.

[kmark]

Thanks for the diagram, I  am thinking that the problem has to be there, I will check it out today.

[The Mighty Gryphon]

You say the brake line is "red" hot. 

Is it hot all the way to the front calipers?  Is it hot going to the master cylinder?  Is the modulator hot, or is it just the lines?  How far up the lines is the heat?  Is there any sign of burnt insulation on the wiring to the modulator?   Does it get hot only when the engine is running and the bike is moving?  Does it get hot when the bike is sitting with the ignition on but the engine is off?

[kmark]

I think I had the red modulator wire switched with the red hot wire from the battery. I think one goes to the front of the relay and one to the back. I believe I had them backwards. As far as the heat went, it heated up just the line from the abs to the front brake reservoir and did so after I had it running, not moving maybe I tapped the front brake and then turned the engine off. That's when she started burning. So now I have to get a new brake line and front master cylinder before trying it again. I imagine the master cylinder must cost an arm and a leg. I'll try one of these guys on line, but I never had any luck with the Beemer boneyard, everything is always sold. Anyway thank to everyone for their help, I'll try to let you know how things work out.