Whining K1100RS fuel pump

[Snowy]

OK, I know they do whine a lot and mine always has but up until now I have only ever heard it while the engine's running when the petrol tank is low. However,yesterday in the UK we were in the 90's temperature wise (a rare event) and I also did a long distance high speed motorway journey (another rare event). When I came off the motorway and had slowed to 40mph I heard the fuel pump whining away extremely loudly. It was so loud I stopped at a garage for a break and to see if I could find anything wrong. It sounded like it was about to self destruct. After 15 minutes it was running quieter but still very noticeable. Fuel tank was half full. After I had visited my mum (it was her 80th birthday), I turned around and did the same ride home. This was now early evening and the temperature had dropped a few degrees. This time there was no recurrence (although I could still hear the pump slightly) of the same high pitched loud continuous whine.

So now I'm thinking it whine's when the fuel in the tank has heated up a lot from the hot engine and air temperatures not from a low level. I'm thinking I noticed it before when the fuel was low because it would have got hotter from the cycled fuel with less volume to disapate the heat. Has anyone else come to the same conclusion? I'm also wondering if this pump is on the way out - is this a sign of impending doom or will the pump go on for ever making the whine continuously? Is there anything I can do to the pump to stop it whining or last longer?

[rbm]

My K does the exact same wining when warm and/or when the fuel level is below half.  It was so loud for me, I got concerned that the pump was about to fail.  I read in another forum that a blocked fuel filter may cause this symptom.  Have you not changed the fuel filter for some time?  If not, it might be worth changing to see if the symptoms disappear.

[sh00ter]

By all accounts, others can weigh in here as well, that's standard operating procedure and it doesn't lessen the life of the pump.  Mine whines when the tank is low or when it's hot, just as you mentioned.

[frankenduck]

When the fuel is low the fuel pump is no longer submerged and the noise generated by it has a larger cavity in which to resonate.

[Snowy]

Just to bring this thread up to date, my fuel pump has been getting progressively louder so much so that with a full tank of fuel I can hear it quite easily while riding the bike (full face helmet and tunes MP3 tunes notwithstanding) and its annoying me now. So I pulled if from the tank this morning as I have decided to replace it either with a cheapish one off ebay or, if I can afford it, a new OEM pump. Mine's a '94 so has the smaller 43mm pump. When I took it out I found that the end of the gauze pre-pump filter had distingrated leading me to make the assumption that dirt ingress had been leading to the pump becoming noiser. Who knows. At least the vibration collar and mount is in good condition so won't need one of those, just the pump and a new gauze filter.

[KJeff]

The pump being broken was the reason I picked up my 96 for a good price - so I have no reference for what the original sounded like. I replaced with the ebay item - actually Euro Motoelectrics. It is smaller in diameter than the original and took some fiddling to mount in the original rubber bushing and get the depth of the intake screen at the correct height at the bottom of the tank. Again with no reference for the noise of the original, it is very noisy - tank empty or full - but really only noticeable at stops.

[grant71]

Strange. i have never heard the fuel pump on my K100 whine,whirr or even whisper. im having a problem getting the engine to fire and i ve been trying to hear some sound. while engine was running i never heard a thing tank empty or full

[Niemand]

...fuel pump has been getting progressively louder so much so that with a full tank of fuel I can hear it quite easily while riding the bike...

I have recently developed the same issue, Snowy.  Like you, I know they usually whine when low, etc.  For the last couple of months, however, mine has gotten loud enough to hear at about 50mph even with a freshly filled tank, full face helmet and ear plugs.  I'm hoping the new fuel filter I have will remedy the nuisance, as it is extremely annoying and worrisome, but I'm holding off on the swap until I pick up new fuel lines to replace all the rubber bits along with it.  I'll be sure to check the sock as well and perhaps soak the pump in Techron for a bit.  I'm only getting out for short rides right now, so hopefully it will hold until then.

I always find it interesting that even when someone mentions that their pump is getting louder, people pile on with the "they all do that" line.  Clearly he was familiar with the standard slightly annoying whine, but noticed a decided uptick in volume.  My recent research on the issue typically ends with threads like this.  Everyone says it's normal, then the rider replaces it to their apparent satisfaction.  (assuming there, due to no follow ups usually.)

Best of luck with it, Snowy.

[Snowy]

Well, I took a gamble and put a bid on one which was on Ebay, the owner saying he had bought it as a spare from Motorworks who is one of the UK's independant parts dealers. I won the pump for £10 plus £5 post. I ordered a new fuel sock which cost £26 plus post and fitted both yesterday. I put about 2 litres of fuel in prior to starting the bike and the result is one very very quiet operation. Took the bike out for a run and everything ran perfectly and I cannot hear the pump unless I put my ear onto the side of the tank. I'm well pleased.  One thing I'm not sure about though concerns the old pump. The fuel sock that came of it was very dirty and I'm now thinking that that may have been the problem all along if that was causing the pump to work harder than it should. I'm not going to fit it to find out though so will keep it as a spare. Any ideas of how to store it? I'm thinking of flooding it with WD40, draining it and then wrapping it up and keeping it on the bike somewhere.

[Niemand]

Nice find on the pump.  Glad to hear you hear yours has been sorted.

Any ideas of how to store it?

I've been wondering the same about storing my whiner as a spare if I come across a cheap replacement.   :hmm:

[frankenduck]

Just store it in a dry place.  I wouldn't bother trying to fill it up with anything but if I did I'd use something like SeaFoam or Techron.