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1Back to top Go down   Motronic Harness Worn Empty Motronic Harness Worn Tue Feb 05, 2013 4:35 pm

Cafe-K

Cafe-K
Silver member
Silver member
So as I was digging through my new project I noticed the wiring harness for the Motronic had worn through the insulation exposing four bare wires. Should I be concerned that this has permanently damaged the Motronic unit and is there a way to test it? Thanks!

Christian

    

2Back to top Go down   Motronic Harness Worn Empty Re: Motronic Harness Worn Tue Feb 05, 2013 4:46 pm

charlie99

charlie99
VIP
VIP
hi christian ....

have a close look at where the actual wear marks are on the loom and what has be causing the issue ...in some cases it could be that some rubber moovement has caused the issue ...and may not yet have shorthed to earth yet .

most smart manufacturers designers will design (where possible) ground signal returns for sensors etc so worst case it will just show full measurement rather than a short circuit condition (but not always possible )

and yes look at some way to insulate the wires ...there are many different ways of doing so heat shrink and all sorts

but try to look at the wiring diagrams, identify the wires in question and see the risks involved with a short to earth condition .


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OMotronic Harness Worn Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

3Back to top Go down   Motronic Harness Worn Empty Re: Motronic Harness Worn Tue Feb 05, 2013 4:49 pm

Cafe-K

Cafe-K
Silver member
Silver member
Thanks all great advice.....from what I recall before soldering the wires back together and covering with heat shrink....don't remember if there was a ground wire damaged (those are all brown correct?)...I'm thinking about undoing my work to double check. The chaffing came from the rear tire....Previous owner seemed to have mounted the Motronic behind the ABS controller. In the meantime I have returned it to its rightful place on top of the battery box!

    

4Back to top Go down   Motronic Harness Worn Empty Re: Motronic Harness Worn Tue Feb 05, 2013 4:55 pm

charlie99

charlie99
VIP
VIP
hmm by the sound of it little chance of a short .

i wouldnt be too concerned ....but write it all down including the colours of the cables

it may become a concern when an issue is found, maybe at some later stage .?


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OMotronic Harness Worn Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

5Back to top Go down   Motronic Harness Worn Empty Re: Motronic Harness Worn Tue Feb 05, 2013 5:04 pm

Cafe-K

Cafe-K
Silver member
Silver member
Well I have already ordered a replacement harness in perfect condition.....(good price on eBay) so I can eliminate future headaches there. My primary concern was having to replace the Motronic. With any luck it survived the abuse and a new harness will have me up and running!

In the meantime I'm going to tear into the old harness to take a look at exactly what was affected.

    

6Back to top Go down   Motronic Harness Worn Empty Re: Motronic Harness Worn Tue Feb 05, 2013 5:08 pm

Themason

Themason
Platinum member
Platinum member
If the bike is running then no problem. You will know if it fails.


__________________________________________________
I live in a parallel universe but have a vacation home in reality :arrow:

1984 K-100RS Alaska Blue w/Parelever and 16V wheels.

1984 K-100RS Metallic Madison stock

1986 R-80G/S w/1000 cc engine

2007 Harley Davidson Street Rod Mirage Orange w/XR1200 wheels, Race Tech, True Track, Works Performance shocks

2007 Harley Davidson Street Rod Vivid Black stock

1993-ish K-100/1100RT/LT hemaphrodite frankenbike thingy to be painted satin black from a rattle can eventually
    

7Back to top Go down   Motronic Harness Worn Empty Re: Motronic Harness Worn Fri Feb 08, 2013 3:42 pm

K-BIKE

avatar
Life time member
Life time member
Hi Christian,
This is a job to do as soon as possible if you are riding the bike because cable harness fires are bad because once they get going any permanently powered wires will short out to others and or the frame and until they burn out from excess current the only way to stop the fire is to disconnect the battery and then hit the fire with some extinguishing material. I found that out 40 years ago when I stopped to help a motorist with an under dash fire and emptied my BCF extinguisher which took out the flames but the wires under the car dash were still glowing and as soon as the gas stopped the fire was away again.
When you put the new harness on be really careful to follow the BMW original route of the harness as that seems to be optimum for avoiding problems. Also take great care not to over tighten the zip ties as that can cause future harness failures by stressing the insulation at that point. Under pressure the insulation can squeeze off the cable exposing bare copper and then it can short to adjacent cables that are similarly affected. I didn't believe it could happen until I saw it with my own eyes on stripping down a multi-core with a fault that had been under point load for several years.
Regards,
K-BIKE

    

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