My ST1100 randomly almost caught fire

Well, it is confirmed:

Most of you were right!

The shop just called. The harness I photographed was NOT an OEM harness. Mice did not cause the problem. And right now, the bike "runs perfect," according to the shop.
The cause: The original Craigslist owner installed a harness directly to the battery. He did not use a fuse. The harness was not connected to ANYTHING (which means whatever it went to was removed before I bought it).

It gets worse. The power leads were not terminated or capped. He left them bare. They touched and the fire started.

I was extremely lucky. They could have touched at any time since I bought the bike. In traffic, in a tight turn, in the garage.

Here's my vow (and I generally do this with ANY vehicle I buy, but never got around to doing with this ST1100). I will never buy or use a new vehicle without thoroughly going through it MYSELF. Ever again.

Kudos and thanks to all of you who helped with advice. This forum is high quality.

Ashley971 said:

It gets worse. The power leads were not terminated or capped. He left them bare. They touched and the fire started.

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Geeze that is bad. If you cut wires with wire cutters the odds are slim that they'd touch something and short. Obviously they should be isolated and insulated anyway. Did the PO leave some length of wire bare? And no fuses. Oy.

Well at least you now know the how. Was that Nav vet the only owner? I'd be tempted to share this info with him. Anyway congratulations on your resolution and resolve.

Thanks for the followup, always appreciated.

John

:yes: thanks for the follow up, as it may also help someone else from the Richard Prior wiring.

Ashley971 said:

The cause: The original Craigslist owner installed a harness directly to the battery. He did not use a fuse. The harness was not connected to ANYTHING (which means whatever it went to was removed before I bought it). It gets worse. The power leads were not terminated or capped. He left them bare.

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Just found this thread. Yeowch.

If you want to understand exactly what happened on your bike, watch the video below. The smoke you saw was the insulation on the wire burning off. The reason everything eventually stopped will come clear if you watch the left side of the battery around the 15-second mark. It probably took longer on your bike because it has a much smaller battery that can't deliver the same current.

https://www.youtube.com/watch?v=vLTkkXajDVc



If people wonder why I harp on properly fusing wiring, this is it.

--Mark

Igofar said:

:yes: thanks for the follow up, as it may also help someone else from the Richard Prior wiring.

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Heh! Heh!

I rode Ashley to Sonoma, California today. She's fine as wine now. So is this forum!

Too late for this response, but next time :

You ( or someone with basic electrical ability ) can replace the wires that were burned up. It's not that difficult. You don't need to replace the entire harness. At worst, remove the harness and have someone with some electrical skill replicate it. It's not a $700 job. I'd do it for about $150.

As far as the "CDI" goes, he must have meant the box that controls the spark, advance, etc. I bought a spare off Ebay for $25. It's now in my top box.

You need to start doing some of your own work, or find someone that can help you or find a good independent MC shop. And there are many good used parts available off Ebay.

Interesting that the PO removed whatever accessories he had. Even more interesting is the way he did it. Had he cut both wires at the same time, he would have had an arc, or a bite out of his cutters, or even started this little blaze when he was doing the work. Wouldn't this have prompted him to tape the ends? This suggests that he cut the wires one at a time. Maybe this was deliberate?

Ashley971 said:

I rode Ashley to Sonoma, California today. She's fine as wine now.

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I see what you did there.

SMSW said:

Interesting that the PO removed whatever accessories he had.

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A lot of people selling their bike do this. Most often certain farkles add little to nothing to the resale value of the bike. Many buyers may not care for some or all of the mods and end up removing them themselves anyway. A seller may make more selling them separately or just reuse them on another bike.

If a person was smart enough to add a farkle that presumably worked he'd probably be smart enough to cut the blue wire first and the rest one at time. Even if he cut a hot and a return at the same time the short would be very momentary. Arc or no arc the seller wasn't concerned about the selling condition. For whatever reason he just removed goodies quick and dirty. So yeah I'd say it was deliberate. Deliberately lazy. Too lazy to bother taping the ends let alone remove a potentially worthless 'harness'. That might even be why there was/were no fuse(s) used. Worse than shade-tree— quick and dirty on/quick and dirty off.

This is a common problem when you purchase a used police motorcycle, as they just cut everything off with a pair of cutters before going to auction.

"If a person was smart enough to add a farkle that presumably worked he'd probably be smart enough to cut the blue wire first and the rest one at time. Even if he cut a hot and a return at the same time the short would be very momentary. Arc or no arc the seller wasn't concerned about the selling condition. For whatever reason he just removed goodies quick and dirty. So yeah I'd say it was deliberate. Deliberately lazy. Too lazy to bother taping the ends let alone remove a potentially worthless 'harness'. That might even be why there was/were no fuse(s) used. Worse than shade-tree— quick and dirty on/quick and dirty off."

And.........some people should not approach a toolbox closer than 200 feet, under court order.

Oldbikefixr said:

And.........some people should not approach a toolbox closer than 200 feet, under court order.

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Yep. Just because you 'can' doesn't mean you should. But stuff happens. Lessons learned.

Blrfl said:

Just found this thread. Yeowch.

If you want to understand exactly what happened on your bike, watch the video below. The smoke you saw was the insulation on the wire burning off. The reason everything eventually stopped will come clear if you watch the left side of the battery around the 15-second mark. It probably took longer on your bike because it has a much smaller battery that can't deliver the same current.

https://www.youtube.com/watch?v=vLTkkXajDVc



If people wonder why I harp on properly fusing wiring, this is it.

--Mark

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that's a bit disingenuous to say that has no too much current . Don't think it would do the same thing with a 9v camera battery and 8 gauge wire

Oldbikefixr said:

And.........some people should not approach a toolbox closer than 200 feet, under court order.

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LMAO!

Ahmen!

Al st1100 said:

that's a bit disingenuous to say that has no too much current . Don't think it would do the same thing with a 9v camera battery and 8 gauge wire

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No, it wouldn't, but that's because the internal resistance of a battery is proportional to its state of charge. Higher resistance and a drop in voltage are a double whammy that keep current in the circuit down. A 9V battery discharges quickly enough that a large wire is going to amass enough heat to damage it. Put the same wire on a car battery and it'll be able to keep the current flowing until the conductor melts. I think that was kind of the point of the title: too much current for the wire.

--Mark

Blrfl said:

No, it wouldn't, but that's because the internal resistance of a battery is proportional to its state of charge. Higher resistance and a drop in voltage are a double whammy that keep current in the circuit down. A 9V battery discharges quickly enough that a large wire is going to amass enough heat to damage it. Put the same wire on a car battery and it'll be able to keep the current flowing until the conductor melts. I think that was kind of the point of the title: too much current for the wire.

--Mark

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AMPS, AMPS !!!