Fuel Pump operation on low fuel

[Summit670]

An A.S.E. mechanic told me many years ago that if your fuel pump is in the fuel tank and you run it too low that the fuel pump can get too warm and that is detrimental to the life of the pump.  He was talking about Pickups but I assume the same would be true for motorcycles.

Has anyone heard about this and do you think it applies to bikes too?

[B.D.F.]

Good advice- running a fuel injected vehicle (motorcycle, car, whatever) out of fuel is hard on the fuel pump because it is a high- pressure pump. There is an oft- quoted myth that running a F.I. vehicle out of fuel causes debris to be sucked into the fuel system because it sucks off the bottom of the tank but that is false- fuel pumps ALWAYS draw from the lowest part of the tank. Running out of fuel just reduces the amount of liquid to lube and cool the fuel pump.

Brian

An A.S.E. mechanic told me many years ago that if your fuel pump is in the fuel tank and you run it too low that the fuel pump can get too warm and that is detrimental to the life of the pump.  He was talking about Pickups but I assume the same would be true for motorcycles.

Has anyone heard about this and do you think it applies to bikes too?

[maxtog]

An A.S.E. mechanic told me many years ago that if your fuel pump is in the fuel tank and you run it too low that the fuel pump can get too warm and that is detrimental to the life of the pump.  He was talking about Pickups but I assume the same would be true for motorcycles.

Has anyone heard about this and do you think it applies to bikes too?

I have heard that type of "urban legend" before and don't believe it.  I doubt it will cause any damage to run with low fuel.  I don't think fuel pumps require much "cooling", and as long as fuel is running through it, that can be the heat transfer (and if the bike is running, the pump is ALWAYS moving fuel).  Sucking air is not a great thing to do, however.

[Mister Tee]

I have heard that type of "urban legend" before and don't believe it.  I doubt it will cause any damage to run with low fuel.  I don't think fuel pumps require much "cooling", and as long as fuel is running through it, that can be the heat transfer (and if the bike is running, the pump is ALWAYS moving fuel).  Sucking air is not a great thing to do, however.

I don't believe that either.  Unless the pump breaks suction from inadequate NPSH due to a low level (which I severely doubt due to the low velocity in the pickup tube) it's either pumping gas or it's not and it doesn't know the difference between a full tank and a low tank.

As for crap clogging the pickup tube, doubtfully an issue on a relatively new vehicle.

[Pokey]

I have heard that type of "urban legend" before and don't believe it.  I doubt it will cause any damage to run with low fuel.  I don't think fuel pumps require much "cooling", and as long as fuel is running through it, that can be the heat transfer (and if the bike is running, the pump is ALWAYS moving fuel).  Sucking air is not a great thing to do, however.

Wanna bet.......I have heard of several Vstroms for example, that the owners ran the tank empty a few times and trashed their pump. Why take the chance, I never have less than a gallon in my tank "never".

[katata1100]

If you were to run out of gas, I wonder if you need to prime the pump though, to get the bike running. I know it is not a gasser, but the fuel gauge on my wife's jetta gave a false reading and she ran out of diesel. I had to loosen injectors to get air out and get it started. I suppose enough cranking to destroy a starter would have gotten it going, but you get my point.
You run out of fuel on any vehicle and that pump will suck in some air. You could refill it, but it still might not start. In that situation, it would be easy to tell the rider that his fuel pump was shot, charge him for a new one and merely bleed air out of the system.

[PH14]

Wanna bet.......I have heard of several Vstroms for example, that the owners ran the tank empty a few times and trashed their pump. Why take the chance, I never have less than a gallon in my tank "never".

There is a difference between running the tank empty and running it low. The OP was referring to running it low. There should be no harm in that.

[maxtog]

There is a difference between running the tank empty and running it low. The OP was referring to running it low. There should be no harm in that.

Thanks, I was about to say that...

[sherob]

I bet the fuel heats up faster at a lower level (1 to 2 gals) than it does at a higher level (4 to full) on a hot summer day.