---

Disclaimer: This will not provide you with a working fuel sending unit. What it will do is allow you to cheaply replace the rusty fuel sending unit with one that will allow power to get to the fuel pump.
Rather than spending $325 on a new unit this fix will cost about 50 bucks.

What you need to buy:

• Fuel level float ring for $5   #62 16 1 459 608 from Euro Motoelectrics
  
• Fuel Systems  in-tank wiring  $20 from Euro Motoelectrics
  
• Motorcycle Scooter Fuel Tank Level Gauge Oil Meter Sender Sensor for WY-125 $13.29 on eBay 
  
  

The new unit looks like this:

I carefully broke the new fuel level potentiometer off the base. When you do this you want to leave a tit of metal protruding up from the base. (I got lucky for mine to break that way.) 
Then you are ready to solder two new wires to the inside base. 
I drilled a small hole into the tit of metal to make soldering easier. 
I even used the existing solder left behind on the center post.
Next, I attached the two rings that fit the post on the fuel pump (from old unit).
You can then either attach the connector from an old unit onto  the outside lead , or as I have done used a new two wire connector on both the bike and this unit, as the oem connectors are know problems.

Finally, I used the new float ring gasket on the new unit and installed it with the four original bolts. The  beauty of this unit is that the bolt holes line up perfectly.
I apologize for the disjointed posts. Couldn't figure out how to add text below a photo. Anyhow I hope this saves someone who is faced with a fuel sending unit that is rusted beyond repair.

Brilliant

Thanks Brian that's good to see. I also checked out the same unit on Aliexpress and it is about $6-8USD. I also notices that there is a gauge that goes with some of the fuel level senders so all in all we are onto a good thing here.

Thanks Matthew and Rick. It is amazing how BMW can ask such a price for basically the same item. I hope this saves a few members some hard earned money.
I've gotten so much valuable advice from this forum's members that I am glad to add to the brain trust.

If anyone goes Brian's route, scrape/sand/file the passivation layer (the gold layer) off the terminals before you attempt to solder new wires on. Solder won't take properly over a protective passivation layer. Also, use something like this (I use it):

https://www.ebay.co.uk/itm/224959202594?var=523834181156

rather than rely solely on multicore solder. Use a high lead content solder as it melts at a lower temperature and is easier to handle when soldering an area that has a high heat sink potential. Lastly, I wouldn't use a soldering iron of less than 35 watts that is equipped with a spade tip to do this job.

Might be better with silver solder, rather than lead based.  Select a 62/36/2 (Sn/Pb/Ag). product. Twice the tensile strength of 60/40 (Sn/Pb) and equal electrical properties.

got the part from ebay, perfect match, getting the soldering done and then off to the races!! Thanks again!!

Hello Brian, great help here as I'm going this route just like this. One question is when going to Euromoto when I search in tank wiring it takes me to basically all the fuel hose options but nothing with electrical wire. Do I need to call them as in a special type order? Laitch directed me to this fix and I have everything ordered but the inner tank electrical wiring. Could the original wiring possibly be used? Thanks again for this fix.