Has a motorcycle ever blown up?

Factual Questions
1

After about 60 miles of riding, I rode my Harley to a gas station and filled up. As is very easy to do, I overfilled a bit, and some gas dribbled down the side of the tank and onto the engine, which was extremely hot. SSSSSSSSSSSSSSS!:eek:

Now, I’m well aware that heat in and of itself will not cause gasoline to burn or explode. Yet, the experience of dribbling gas onto a very hot surface is still spooky! Is there any chance at all that this could be dangerous, and has a bike ever blown up because of this? What I’m nervous about is when I restart the bike, the spark plug being right there by the engine.

2

Uh, it most certainly will; the autoignition temperature of a standard unleaded gasoline can be anywhere from 260 to 460 degrees C (or 500 to 860 deg F): FAQ: Automotive Gasoline Web Page.

Now, it’s true that your engine (if it’s running properly) will probably not be that hot on the outside; but there’s certainly enough heat there to volatilize a significant (and combustible) amount of gasoline. A properly installed spark plug, however, should not be throwing sparks outside the engine; the only way what you’re suggesting could happen is if your engine’s cylinders were taking in spilled gasoline through the valves, or something like that.

3

They blow up all the time in the movies!

I’ve seen a few burn (once when I was a little kid my mini-bike caught fire while I was riding it), but I haven’t seen any actually explode.

4

I should have said it usually will not cause it to burn/explode, meaning it doesn’t happen that often, with the exception of very extreme heat/circumstances.

5

But the plug wire is in poor condition, there’s a chance for an arc to the jug, no?

6

I’ve never seen one blow up, but in the slight chance that you might have dribbled a bit of gas on the heads, and if the plug wire was arcing to ground, I don’t think you would have the amount to really have it “explode”. It may catch fire, but I doubt it would explode. However, this is just WAG, do not test my theory.

I’ve had car engines catch on fire in my shop before, and they did not “explode.” It may have melted vacuum lines and wires, but I’ve never seen anything explode…plus people were around to take care of it before it got worse.

7

I actually had a bad plug wire on this bike (it’s since been fixed). The plug was in fact arching a spark to the outside rocker cover. It was actually pretty; like a pure blue bolt of lightning. But it drew a lot of power out and the bike ran like crap. I think that if there was gas there (and that is an area that gas did drip on) I might have blown up! that’s why I’m a little spooked now.

8

I think that for the bike to blow up, your fuel tank would have to be at least half-empty so there was enough air in it to support rapid combustion, and the fuel/air mixture in the top of the tank would have to be exposed to a spark, flame, or temperatures that would make your thighs very uncomfortable as you straddled the tank. Just guessing.

9

Try running your bike on methanol!!!

10

God, there are times when I wish they would…particularly the one owned by that little bastard that rides his dirt bike next to my property on a Sunday afternoon.

11

I’m pretty sure that the outside of a single-wall exhaust pipe can reach these temperatures. The chrome on these pipes usually turns blue and I’ve seen a few that glowed red at night (probably because the bike needed a tuneup and/or needed the carburetor set up.)

12

Can you spill gas on a motorcycle (or car engine) and start a fire /explosion?
The answer would be a yes, but with several qualifers.
Gas will only burn in a limited range of air fuel mixtures.
First off in the OP the motorcycle was off while being fueled. While the exhaust may well run above the auto ignition temp of gas, as the exhaust pipes don’t have a lot of mass they cool fairly quickly (mind you they don’t have to be cold, just below the ignition temp of gas) The other arguement against a fire/ explosion is that being off there is no electrical current flowing anywhere, so no chance of a random spark.
Now what will happen is the gas will evaporate and if an igniton source were to be present before the mixture gets too lean there would be a fire/ external explosion. By external explosion I mean that the vaporized gas will go “WHOOMP” not the entire bike blowing itself over the gas station.
But since the bike is parked outside and gas fumes are heavier than air, they don’t linger much in cases like this and will dissapate fairly quickly. (The OP said some gas, I take this to be a small quanity)

Personally, I would be far more concerned about a gas leak on a car (or bike) parked in a garage where a water heater is located.