Burnt wiring

[Zombie Master]

I'm worried about the extent of the damage to adjacent wires, and how far that my have gone down the loom even beyond the connection board in the headlight. Am I looking at a full harness replacement?

[Bamboo812]

You'd better hope not. They are currently in the $670 range...

[Zombie Master]

You'd better hope not. They are currently in the $670 range...

Without disassembling the main harness, how will I determine the damage? I can't believe BMW didn't put a fuse on this.

[Zombie Master]

You'd better hope not. They are currently in the $670 range...

$184.@ BOBs

[Bamboo812]

How are you determining which harness you need? The Max fiche shows the R100S as only up to 1980. There is a parts source that uses the VIN to ensure a match, but I can't find it. Maybe RealOEM? Find where the burnt wire exits the harness and look for damage there. If so, then it's a matter of carefully cutting open the sheath and replacing that wire, while looking for places that melted through to other wires.

[moosehead]

No no....Bob's certAinly not a problem.

I'm just used to Motobins etc. never used Bob's BMW but they're big and probably great supplier.

As I said , I got lucky over on IBMWR.org when replaced main harness on my 77 S. Actually harness I used was off an 78.

Good luck in the hunt.

Sounds like the fried wires may have done some damage to headlight wires too? Working in the bucket was not one of my favourite activities but patience will be a virtue checking it all out! Good luck. Take your time.

[enigmaT120]

What shorted out? Or was it just a job that should have been done with the battery disconnected first?

[Zombie Master]

What shorted out? Or was it just a job that should have been done with the battery disconnected first?

My eyes aren't what they used to be and I just pushed it onto ground. The wire to the clock is always hot. I've been meaning to put an in line switch on it for many years, so when I go away the battery isn't drained off. I should have done it. The fact that the circuit is not fused is a failure of BMW.

[grant81rs]

Gidday,

ZM - I am currently in the middle of replacing the complete wiring and loom on my 1978 RS, now a week or so back I had no idea of wiring at all, had always shied away from it and ticked it off my book as to bloody hard.

So a few days ago I jumped in with a mate and started laying down the replacement loom that I brought of ebay, I had a lot of diagrams and drawing from the web, but I did not really know what to expect, well actually I did think it was going to be a little easier than it turned out, you see where we came unstuck was that the loom I purchase although in excellent condition was from a US speck 78 RS and my old 78 is a UK speck bike, this I did not know at the time and yes there are slight differences only in the headlight switch and a couple of extra wires hanging around that completely threw us off track for the day, we gave up and hung our heads in same, you see my friend that helped me was Ray the fella that spent 16 months helping me to restore the old 1928 Chev and we had guns blazing that morning in the resto shed we started on the RS wires, "No problems, we'll have it running by lunch" was the approach, we can rebuild an old chevy so this will be a walk in the park....

RS, One.... Over Enthusiastic Chevrolet Restorers, None

So I have sat and read, read and read the wiring diagrams, read about relays and different things and it is very slowly coming together for a novice, I have racked up a decent phone bill to SteveD this past few weeks to btw and I have stood at the bike on the lift for a few hours holding the coloured diagrams and followed each and every exposed wire on my bike over and over, and yes it is all starting to sink in slowly, sorry very slowly!!

I now have to convert the US loom to the UK specked loom for my on/off headlight switch, not a hard gig I have been told but it is a little confusing for me just the same, but we will see what happens and do you think I am shit scared of hitting that start button once I have a few things back together F#$K yes!!, the bike shall be wheeled out of the shed and a fire extinguisher by my side...

Anyway mate I wish you well, sorry I cannot help in the tech department of your question but just jump in, open it up and have a look about, its all replaceable at the end of the day..

Best of Luck!!

[Zombie Master]

Well I got the new harness for the clock and volt meter. $55. USD. I got lucky in the headlight shell, with just a few scorched wires that I was able to patch without involving the main harness at all. The rubber grommet going into the headlight shell insulated the shell from any damage.

The new harness wires are lighter gauge, which may be a good thing in the case of another short. The bulbs were burnt out in both gauges, which worried me, as I was wondering if those instruments were toast. I tested both with a 9 volt battery and they both seem to be working. Voltmeter actually read 9 volts!

I was able to get new bulbs in stock from the local BMW dealer. Amazing for a 30 year old bike. Try that with your Honda!

I've got the new harness routed through the headlight shell, and everything hooked up to the circuit board in the headlight shell. I'm going to be installing an in line fuse for the clock, as I should have 30 years ago. I'm wondering what an appropriate fuse would be?. Anybody know a good alternative headlight bulb for the H4 that will plug in? The bulb still works but there must be a more efficient one available. The headlight lens is cloudy, is that cleanable IYO? Any methods work well for improving lens clarity?

I guess I should start it up for a test before I install the fairing. I'm thinking a quick disconnect battery ground would be handy. Anybody know of a good one? I look at my burnt faring harness and hang my head in shame. I don't know whether I should throw it away or hang it on the wall of shame, as a reminder of how, in a moment of inattention you can fuck up. A humbling experience.

Thanx for your comments.

Next....lube the spline.