Repair of the Christmas roasted FJ

[aviationfred]

I have begun the repairs on my FJ that caught fire during my vacation to South Carolina and Florida. The carbs are on their way to RPM for a good cleaning and going through. The actual damage is much less than I thought. The only factory wire damage is at the red circle in the photo. The only severe damage was to the oil level sensor/Neutral switch indicator wires. The green connector in the photo, the wires lay under the UNI pods and route behind the engine (red circle). The black plastic sheething in the red circle area as you can see is completely melted and fused to the wires. The heat shield shows the most heat damage at the left rear. I believe that this is where the fire began. A chafed wire... built up chain lube.... catches fire....ignited oiled UNI pods.... melts fuel line at the under tank fuel filter...

There really isn't any more damage other than the right fairing infill panel.

[ZOA NOM]

Thank God you acted quickly and were in the right place.

[aviationfred]

I am considering ordering one of these to keep in my top box. 

https://www.ebay.com/itm/Portable-Lightweight-Household-Car-Use-Powder-Fire-Extinguisher-for-Hotel-AH-/254025707428?skus=Color:blue&varId=553364343362


Fred

[Tuned forks]

Considering our bikes reputation for self-immolation, that seems like a really good idea.  How fast can you get into your box in an emergency situation Referring to an adrenaline fueled moment when we revert to caveman instincts.  I know I'm not fast getting into the hard luggage.  Except for theft, I'd like to mount something like that to the outside of the bike.

Joe

[ZOA NOM]

I barely had time to grab my tank bag. If it had been strapped on instead of just magnets, I wouldn't have been able to. That said, I really wish I had one when mine burned down. The worst feeling is standing there watching it burn, helpless.

[aviationfred]

I really wish I had one when mine burned down. The worst feeling is standing there watching it burn, helpless.

Having seen the photos of your FJ and the aftermath, Your mishap actually entered my mind as I ran into the Restaurant.


Fred

[balky1]

I am considering ordering one of these to keep in my top box. 

https://www.ebay.com/itm/Portable-Lightweight-Household-Car-Use-Powder-Fire-Extinguisher-for-Hotel-AH-/254025707428?skus=Color:blue&varId=553364343362


Fred

Just an advice, buy such things only in US stores. That way you can (probably) be sure it complies to the neccessary standards and that it is safe. After all, it is a pressurized container and I believe you have some regulations in the US that monitor such things.

[ribbert]

...... I believe that this is where the fire began. A chafed wire... built up chain lube.... catches fire....ignited oiled UNI pods....

[TexasDave]

...... I believe that this is where the fire began. A chafed wire... built up chain lube.... catches fire....ignited oiled UNI pods....

Fred you wouldn't need a fire extinguisher with a Triumph Tiger. They have fuel injection and don't catch fire. Just sayin..........      

Dave

[racerrad8]

Fred,

Is is your belief those wires chaffed and caused the source of ignition?

The reason I ask is because those two sensor wires are grounding circuits that illuminate the specific warning light. If either of those two wires chaffed and contacted each other or the case, you would have only had a dash warming light stuck on.

Once we get the carbs and perform an autopsy, maybe the source can be determined. I recall you saying in one of the original posts, the engine was missing when you pulled into the parking lot. That and the running issues just prior to departing on the trip is in my opinion pointing to fuel flooding out of a carb or two.

We will be very methodical in diagnosing the carbs when they are disassembled.

Randy - RPM

[aviationfred]

Fred,

Is is your belief those wires chaffed and caused the source of ignition?

The reason I ask is because those two sensor wires are grounding circuits that illuminate the specific warning light. If either of those two wires chaffed and contacted each other or the case, you would have only had a dash warming light stuck on.

Once we get the carbs and perform an autopsy, maybe the source can be determined. I recall you saying in one of the original posts, the engine was missing when you pulled into the parking lot. That and the running issues just prior to departing on the trip is in my opinion pointing to fuel flooding out of a carb or two.

We will be very methodical in diagnosing the carbs when they are disassembled.

Randy - RPM

The source and cause of ignition is really guess work on my part. I am trying to work on an educated guess from the damage that I am finding while doing repairs and the location of the most damage. The worst wiring damage is located in the fed circle of the posted photo. Also that is the same location that all of the carb overflow hoses were routed. I left the hoses attached for the carbs. You will be able to see the heat damage on the hoses.



Fred

[ZOA NOM]

I really wish I had one when mine burned down. The worst feeling is standing there watching it burn, helpless.

Having seen the photos of your FJ and the aftermath, Your mishap actually entered my mind as I ran into the Restaurant.


Fred

Well, if I can save just one FJ's life, it's all been worth it!

[Pat Conlon]

Rick, remind me, you split a fuel line at the fuel filter, correct?

[ribbert]

The source and cause of ignition is really guess work on my part......

Fred

Fred, I'd be surprised if anything other than fuel/fuel vapour could ignite down there, it would need a spark to set it off and the alternator is the most likely source for that. Hot engines, hot exhaust pipes, hot wires won't do it.

The engine stumbling just beforehand sort of adds weight to carbs flooding.

Noel

[Firehawk068]

I would agree with Noel.
Fuel is actually very hard to ignite without a spark. A hot engine will not ignite Gasoline.
There has been a few instances where I had fuel pour/spray directly onto my just-turned-off FJ engine. It simply boils off and flashes into vapor instantly. No spark + No Ignition.
Built-up lube/oil is absolutely impossible to ignite...............You could have it dripping directly on the hot exhaust of a running engine for days and it would not ignite (I have actual real-world experience with this)
Unless you have an open flame, you will not light any oil/lube on fire. A spark will not ignite it either.

You would've had to have fuel overflowing from somewhere, flashed into vapor from the hot engine, and an actual spark from either: a live power wire shorting to ground, a spark-plug wire arcing outside it's insulation, or as Noel said, the alternator (there is sometimes some arcing at the brushes during operation)