Been reading messages from all those looking for a new fuel sender, as the originals getting (very) scares.. 

So understand the original goes from 3-108 Ohm. 

As I don’t believe BMW developed this sender for just our bikes, did a quick search for that resistance band and fuel sender - got this back 
https://forum.ih8mud.com/threads/bench-testing-fuel-sending-unit.1278081/

This unit (PN 83320-3520)  Even looks similar except the float.  And from there found that the Toyota TJ40 and various BMW cars used this. 
So those might be more readily available (and still new). 

You obviously still need to get this fitted and the float working - but if you have a broken original, this might be a way to get parts to restore original ones… 

Just a thought - I didn’t need to do this yet! 

Cheers,
Y

The problem with our sending units is that virtually every other application mounts the sender on the TOP of the tank while our senders are mounted on the BOTTOM. 

Because of this difference any sender except for the "official" BMW unit will read backwards showing empty with a full tank and full sometime around when the tank is empty.

This isn't that big a deal, it is possible to build an inverting amplifier to reverse the sender's output so the gauge reads the level properly.  The problem is in the low fuel warning on bikes not equipped with a gauge.  It is possible to build a comparator circuit that will trigger the low fuel light, but now things are starting to get a bit complicated. 

Perhaps one of the inmates with more working knowledge of op amps than myself could come up with some circuitry that could be packaged in such a way as to be a plug and play installation.  This is the only real solution that I see.

I have a digital gauge, I stick my finger in and no fuel on the digit means I have used some so I check my trip meter.

The most critical function of the FLS is powering the fuel pump. If your trip odometer is working then you could just start looking for gas in at about 150 miles or so and live without the idiot light and/or gauge.

Agree .75 - that is a way. I know my way around electronics, and that what you describe is all possible.

One day I give that unit I found (or similar) a go anyway, to look at the internals. I’ve got a strong feeling there components on it that will help us fix the k100 fuel sensors

Others - I don’t have an issue yet…. All works well, just thinking here with the hive

I would be interested in an fls if someone created a working model that mimicked the OEM. Recently purchased a k75rt and when I needed one 5 years ago they were available at Eme for around $300. In my search for one recently I found they are unobtainable. While searching and reaching out to various bmw forums I found that I was not the only one looking for this item. There seems to be a market for them.

I emailed Euromoto Electrics to see if they are working to find a third party to make a K FLS given the high demand. They responded that they are working on this but it isn't easy and can't be done overnight. Hopefully they'll have something soon.

Good to hear. I would imagine the demand would be increasing. I wonder if Enduralast would make one.