Author Topic: 93 K1100LT blowing fuse 5?  (Read 3007 times)

Offline Jackson

  • Motobrick Curious
  • Posts: 15
93 K1100LT blowing fuse 5?
« on: August 10, 2020, 09:04:24 PM »
Hello all,

I am new to this forum but have been reading through so many posts all day today and yesterday trying to find something to help me.

I recently bought a 1993 K1100Lt. Yesterday I went riding with a buddy for about 6 hours and nothing was wrong. Went to his house and left late at night but when I got to the top of the neighborhood the bike just stopped on me.

Fuel pump was not priming and gear indicator, neutral light, temp light, etc. were not coming on. Found out that fuse 5 (motronic fuse) was blown so I threw another fuse in and it started right up good as new but it blew again after about 2 or 3 minutes of riding. I have been trying to trace the problem with the wiring diagram and reading through the motronic training book but I can not put my finger on the problem.

It was late last night and I had work this morning so did not want to fool around with it too long. Was talking to a buddy and trying to figure it out but all we could come up with is a faulty Motronic unit or ground fault somewhere.

Is there any genius insight that any of y'all have on where the problem could be? Could it be the relay? I am young (20 year old college kid!) and dumb and this is my first bike so excuse my lack of knowledge but I am hoping to learn a great deal from this forum. Thank you for any help you can offer!
  • Clemson College Town USA
  • 1993 K1100LT

Offline volador

  • ^ Quintessential Motobricker
  • Posts: 1167
  • NEEDS MORE CHROME
Re: 93 K1100LT blowing fuse 5?
« Reply #1 on: August 14, 2020, 05:23:42 PM »
That is a unusual fuse to blow. Motronic failure is rare in a K1100 and to happen after the continuous hours of use, but anything is possible.

Fuse#5 may have factory accessories like aux. lights, radio, alarm, etc... that maybe causing a short

Lack of knowledge and proficiency is no reason to speak of yourself in that manner. We all started somewhere... don't ever speak of yourself like that again.
  • NYC NY
  • 1991 K100RS 1993 K75S ABS
5 BOROUGHS SISYPHEAN SOCIETY  MAINTAINING THE OBSESSION

Offline daveson

  • ^ Quintessential Motobricker
  • Posts: 1268
Re: 93 K1100LT blowing fuse 5?
« Reply #2 on: August 14, 2020, 09:35:15 PM »
Not familiar with the k1100 but here's an option that might be worth considering.

Unplug the consumers that depend on fuse 5 and replace fuse 5 with your multimeter set to 20 Volts. With the ignition on you should read 0 Volts. If you read 12 Volts, wiggle (or unplug)  the different wires till you find the one that drops it from 12 to 0. If not, the short might be in one of the consumers (including its wiring)

Consider especially any circuit to fuse 5 that has had recent work done, or is not original.
  • Victoria, Australia
  • Current; '85 K100RT~100,000km; four other bricks. Past; Vulcan 1500, V Star 650, KLX 250(dirt bike) TT250(dirt bike)

Offline Jackson

  • Motobrick Curious
  • Posts: 15
Re: 93 K1100LT blowing fuse 5?
« Reply #3 on: August 15, 2020, 12:52:33 AM »
So I checked out the bike today cracked open my boxes of fuses I had. The fuse that I used to replace and see if it would blow again was a spare fuse on fuse 10.

When I put a brand new 15 amp in the bike hasn’t died yet. I rode for about an hour to get it home from where I left it last weekend and it ran well.

I would assume the fuse may have been old and starting to degrade? Either way the bike is running and getting me places. If it happens again I’ll start hooking up my ammeter and multimeter to diagnose.

Thanks for the help and suggestions. Can always use more “tools” in the bag.
  • Clemson College Town USA
  • 1993 K1100LT

Offline volador

  • ^ Quintessential Motobricker
  • Posts: 1167
  • NEEDS MORE CHROME
Re: 93 K1100LT blowing fuse 5?
« Reply #4 on: August 15, 2020, 03:06:32 AM »
All K1100 fuses are 15A

Factory Service Manual, Torque Specs & Riders Manual download from the world famous Motobrick library

Some links for your K journey

Just bought a 2V

Just bought a 4V

Check parts compatibility with BMW MAX Microfiche, BOBS BMW, REAL OEM

https://shop.maxbmw.com/fiche/PartsFiche.aspx

https://shop.maxbmw.com/fiche/PartsSearch.aspx

https://parts.maxbmw.com/BMW___BmwMotorradK.html

https://www.bobsbmw.com/store/microfiche/BrowseSeries.aspx

https://www.realoem.com/bmw/select.do?kind=M&arch=1

https://www.ascycles.com/BMW-Motorcycle-Parts-Fiche

Cross reference parts like Bosch pn#'s, etc....  http://partsplusecat.com/
No spaces in the part number

Parts Vendors

https://www.beemerboneyard.com/

https://www.capitalcycle.com/

https://www.euromotoelectrics.com/

https://www.tills.de/

Headlight relay stuff if you chose to add one

https://www.motobrick.com/index.php?topic=268.0

http://www.motobrick.com/index.php/topic,4962.msg30932.html

http://culayer.com/product/matchbox-headlight-relay/

http://easternbeaver.com/Main/Wiring_Kits/H4_Kits/h4_kits.html  Eastern Beaver site is a great reference for electrical connectors,plugs, etc...

http://www.k100-forum.com/

http://www.kforum-tech.com/Tech-page.html

http://www.kforum-tech.com/electrical/EFI/bike-wont-start-EN.htm

http://www.kforum-tech.com/Downloads/electrical/diagrams/interactive_diagrams.htm

http://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/k100tshoot/K100.Troubleshoot.Start.2018.pdf

http://kbikeparts.com/index.htm

http://www.kbikeparts.com/classickbikes.com/ckb.tech/ckb.new2k.htm

http://www.kbikeparts.com/classickbikes.com/ckb.tech/ckb.tech.toc.htm

http://www.eilenberger.net/K75S/IgnitionSwitch/

http://www.verrill.com/moto/moto.shtml

this site has a lot of good info and breakdown pictures in the tech and tech resources sections for K1100 alot of the parts are on K75 & K100

http://www.k11og.org/forum/index.php?sid=2df953dde5715fd9001fbe69edec5ad0

https://ibmwr.org/index.php/k-bike-tech-articles/

This site has all kinds of technical specifications on all the BMW models    http://www.bmbikes.co.uk/mechanicalpages/kseriesmechanical.htm

http://largiader.com

http://bmwk10075abs1fix.web.fc2.com/index.html  Toshi ABS site

Good Luck
  • NYC NY
  • 1991 K100RS 1993 K75S ABS
5 BOROUGHS SISYPHEAN SOCIETY  MAINTAINING THE OBSESSION

Offline Laitch

  • Faster than a speeding pullet
  • Administrator
  • ^ Quintessential Motobricker
  • Posts: 11299
Re: 93 K1100LT blowing fuse 5?
« Reply #5 on: August 15, 2020, 06:42:04 AM »
When I put a brand new 15 amp in the bike hasn’t died yet. I would assume the fuse may have been old and starting to degrade?
It is accurate to assert that these old motos' fuses can degrade; furthermore, the sockets into which they fit can oxidize so they should be inspected also. The fuses can be replaced by whichever fuse at the hardware or auto parts store has the correct blade width and amperage. They don't need to look exactly like the OEM version.

An important tool for Bricks is a can of DeoxIT D5 electronic contact cleaner. All electrical connections should be cleaned and treated with DeoxIT. Some auto parts stores might have it but I get mine at a musical instrument dealer who has a large stock of electric instruments and electronic equipment. Of course, you can buy it online. You should make it your task to clean connections wherever you find them until you've cleaned all of them.

Good luck with your Brick.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles

Offline volador

  • ^ Quintessential Motobricker
  • Posts: 1167
  • NEEDS MORE CHROME
Re: 93 K1100LT blowing fuse 5?
« Reply #6 on: August 15, 2020, 04:20:19 PM »
  • NYC NY
  • 1991 K100RS 1993 K75S ABS
5 BOROUGHS SISYPHEAN SOCIETY  MAINTAINING THE OBSESSION

Offline Jackson

  • Motobrick Curious
  • Posts: 15
Re: 93 K1100LT blowing fuse 5?
« Reply #7 on: August 16, 2020, 12:27:47 PM »
Well I think I know the culprit. Now every time I start it and pull the clutch in the fuse pops. Any insight on where that could be? Or what I should do to fix it?
  • Clemson College Town USA
  • 1993 K1100LT

Offline volador

  • ^ Quintessential Motobricker
  • Posts: 1167
  • NEEDS MORE CHROME
Re: 93 K1100LT blowing fuse 5?
« Reply #8 on: August 16, 2020, 04:26:39 PM »
Probably the clutch switch or switch wires causing a short.
Trace the wires from clutch perch to underneath the tank should be a connector to left of the frame center tube.
  • NYC NY
  • 1991 K100RS 1993 K75S ABS
5 BOROUGHS SISYPHEAN SOCIETY  MAINTAINING THE OBSESSION

Offline The Mighty Gryphon

  • Administrator
  • ^ Quintessential Motobricker
  • Posts: 6843
Re: 93 K1100LT blowing fuse 5?
« Reply #9 on: August 16, 2020, 08:35:15 PM »
Probably the clutch switch or switch wires causing a short.
Trace the wires from clutch perch to underneath the tank should be a connector to left of the frame center tube.

Check the wires from the clutch switch where they pass the steering head. 
  • In my garage in Marilla, NY
  • '91K100RS White/Blue
Current:
'91 K100RS16V "Moby Brick Too"

Past:
'94 K75RT "Ilsa, She Wolf of the SS"
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline Laitch

  • Faster than a speeding pullet
  • Administrator
  • ^ Quintessential Motobricker
  • Posts: 11299
Re: 93 K1100LT blowing fuse 5?
« Reply #10 on: August 16, 2020, 09:15:41 PM »
G = Green  B/G = Black/Green  The boxed area indicates the connector. The arrow indicates the wire to the coils. The combined switch, right contains the kill switch.

The clutch switch, its cable and connector.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles

Tags: