Fire extinguisher

Fuzzbuster

Fuzzbuster

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So, the other day one of my bikes had a small fire. Fortunately, I put it out quickly enough with a fire extinguisher and there is very minimal damage. I was always under the impression that it is not as easy as you think to start a fire. You need ideal conditions and the 3 components, air, fuel and ignition source. I think I may have become slightly complacent with handling gasoline. I am always transferring from container to container, working on open running carburetors, testing bikes with alternate fuel cells, testing fuel pumps and so on! The fire appears to have originated at the overflow tube for the carburetor. After pulling the carbs and dismantling them I noticed the suspect carb float bowl had less fuel inside than the other 3. Is it possible that because there was less fuel in that particular float bowl that there was more vapour/ air mixture and this exited the overflow tube and was ignited by the spark plug from the inside? There were no signs of fuel on the exhaust pipe, no loose wiring, bike was outside the garage on the driveway. I had just started the bike after draining the float bowls and it was running for maybe 30 sec when I noticed a orange glow from under the tank and airbox.
The take away here is gas is really flammable and if you are going to be working with it make sure you have a good 5 lb + extinguisher near by. IMG_0263.jpeg
 
Had to be a loose wire somewhere. Doubt it was static.
I have an extinguisher on each floor of the house and one in my 5x8 trailer.
 
I suspect ignition was heat not spark. A little gas dribbled on the headers is more plausible than a spark plug lighting an external fire.

"I had just started the bike after draining the float bowls" "After pulling the carbs and dismantling them I noticed the suspect carb float bowl had less fuel inside than the other 3". Why was their fuel in the float bowls if they were drained? How was the engine running if they were drained? Something does not compute.
 
Did you spray extinguisher while the motor was running?
If you DID, you ran a very good chance the motor ingested some dust... that gets in behind the rings and packs the rings
 
GreyGhost said:
I suspect ignition was heat not spark. A little gas dribbled on the headers is more plausible than a spark plug lighting an external fire.

"I had just started the bike after draining the float bowls" "After pulling the carbs and dismantling them I noticed the suspect carb float bowl had less fuel inside than the other 3". Why was their fuel in the float bowls if they were drained? How was the engine running if they were drained? Something does not compute.
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There was zero flame near the mid pipe, zero gas on the pipes, sub frame, frame or in the belly pan. I don't even think the engine or pipes would have gotten hot enough at that point?
 
Wingboy said:
Had to be a loose wire somewhere. Doubt it was static.
I have an extinguisher on each floor of the house and one in my 5x8 trailer.
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No loose wires that I can see. Would the battery or some other component be the ignition source?
 
Fuzzbuster said:
No loose wires that I can see. Would the battery or some other component be the ignition source?
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Explain more about what happened. You said that the float bowls were drained but that the engine was running and they still had gas in the bowls. My suspicion is still related to gas ending up somewhere poor as part of the "draining" process. Spark could have come from the starter, relays or somewhere else to get the fire going and it took you a few seconds to see it.
 
bitzz said:
Did you spray extinguisher while the motor was running?
If you DID, you ran a very good chance the motor ingested some dust... that gets in behind the rings and packs the rings
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I also only gave the fire a direct short blast from the extinguisher. I didn't unload the extinguisher. Prior to pulling the tank and carbs after the fire I left the bike outside over night just in case and then blew everything off with compressed air to get rid of the extinguisher spray.
 
GreyGhost said:
Explain more about what happened. You said that the float bowls were drained but that the engine was running and they still had gas in the bowls. My suspicion is still related to gas ending up somewhere poor as part of the "draining" process. Spark could have come from the starter, relays or somewhere else to get the fire going and it took you a few seconds to see it.
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Drained the float bowls.
Fresh gas in the tank.
Reconnected everything and started. It took a couple cranks to get it going. Once running, choke off, I was admiring the beautiful engine sounds, walked around to the exhaust side and noticed the orange glow. Said oh ****! Killed the engine, went and grabbed extinguisher. Still orange glow so used extinguisher. Thats it!
 
Fuzzbuster said:
Drained the float bowls.
Fresh gas in the tank.
Reconnected everything and started. It took a couple cranks to get it going. Once running, choke off, I was admiring the beautiful engine sounds, walked around to the exhaust side and noticed the orange glow. Said oh ****! Killed the engine, went and grabbed extinguisher. Still orange glow so used extinguisher. Thats it!
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Interesting. So the gas was on and you drained and refilled the float bowls. I've never done that. If I'm draining, they stay empty for the off season. Given that the bowls were refilling at the time, maybe the valve didn't seat properly and puked some fuel out the overflow?
 
Fuzzbuster said:
............walked around to the exhaust side and noticed the orange glow. Said oh ****! Killed the engine, went and grabbed extinguisher. Still orange glow so used extinguisher. Thats it!
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You have some electrical issue causing a spark or arcing that is igniting the spilled / drained gas.
 
GreyGhost said:
Interesting. So the gas was on and you drained and refilled the float bowls. I've never done that. If I'm draining, they stay empty for the off season. Given that the bowls were refilling at the time, maybe the valve didn't seat properly and puked some fuel out the overflow?
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I sometimes drain my carbs just before the first start of the season depending on how long the bike was stored for. I prefer to keep the floats full to avoid any residual fuel that's unavoidably left behind when draining from evaporating into that yellow crusty stuff.
 
GreyGhost said:
Interesting. So the gas was on and you drained and refilled the float bowls. I've never done that. If I'm draining, they stay empty for the off season. Given that the bowls were refilling at the time, maybe the valve didn't seat properly and puked some fuel out the overflow?
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I was not prepping it for the end of the season. I rebuilt the bike and was just getting it going. I will prep all my bikes for storage next month!
 
GreyGhost said:
Interesting. So the gas was on and you drained and refilled the float bowls. I've never done that. If I'm draining, they stay empty for the off season. Given that the bowls were refilling at the time, maybe the valve didn't seat properly and puked some fuel out the overflow?
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I had one of my other bikes puke fuel out the overflow but it was alot more and went all over the ground. I cleaned the carbs on that one put it back together and it ran no problem. This one didn't have fuel every where? Like nothing. It was more like a vapour?
 
Fuzzbuster said:
I had one of my other bikes puke fuel out the overflow but it was alot more and went all over the ground. I cleaned the carbs on that one put it back together and it ran no problem. This one didn't have fuel every where? Like nothing. It was more like a vapour?
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As it was filling the bowl, gas vapour should get pushed out the overflow. I would be surprised if that was enough to burn but maybe it was. Seems like a combination of barely available fuel source and a random spark (if it was only running for a few seconds, you are probably right that there shouldn't be enough heat available).
 
Just a heads up.... ABC extinguishers are usually some combination of monoammonium phosphate, ammonium sulfate and whatnot....what is left behind is highly corrosive specially to electronics. Make sure everything is thoroughly cleaned up otherwise future problems can arise.

Obviously fire is much worse....
 
backmarkerducati said:
Just a heads up.... ABC extinguishers are usually some combination of monoammonium phosphate, ammonium sulfate and whatnot....what is left behind is highly corrosive specially to electronics. Make sure everything is thoroughly cleaned up otherwise future problems can arise.

Obviously fire is much worse....
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I've contemplated having a CO2 extinguisher around as a first line. They are pretty expensive new and I haven't come across any that were expired (and therefore very cheap).
 
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