Wtb fuel sending unit 1986 k75

[Christopherguzzi]

I was hoping to save the one in my bike that had been sitting in storage for many years, but alas, it's no good afterall. :(.  I'm near St. Paul Mn for shipping estimates.  Thx. 

[jakgieger]

New from BMW are available...

[BrickMW]

EME sells them new as well...


What is it you were unable to save about yours? Just low fuel warning light? Fuel pump wiring?


Your moto doesn't use the variable wiper which is most likely destroyed...

[Laitch]

Your moto doesn't use the variable wiper which is most likely destroyed...

What is the meaning of the sentence I quoted, BrickMW? If his bike doesn't have a "variable" wiper then there is nothing to be destroyed. It's also unlikely to have been designed to use destroyed parts. If your statement is a kōan, it's a beauty.

[BrickMW]

What is the meaning of the sentence I quoted, BrickMW? If his bike doesn't have a "variable" wiper then there is nothing to be destroyed. It's also unlikely to have been designed to use destroyed parts. If your statement is a kōan, it's a beauty.

It is my understanding that all K Brick's have a fuel sender assembly that consists of a two part wiper. At the back of the assembly is a switch that operates the low fuel light, and a simultaneous variable resistance winding mounted in the front of the assembly that would be used for a fuel gauge.


My K75c does not have a fuel gauge, I'm assuming his doesn't either. :dunno2:  So I cut the wires and removed the winding board, which had little to no winding left, more like a wire brush.. aka "destroyed"


My K75c does not have a low fuel light warning anymore either, switch was not salvageable. So I study the trip odometer and know my range.


However, my "defective / damaged" fuel sender still does a bang up job at sealing the gaping hole in the bottom of my fuel tank as well as passing power and ground wires to my fuel pump. Not meeting one or both of these two conditions would be the only reason I would consider replacement absolutely necessary.


$200 for a low fuel light doesn't compute with me.. but I'm not so much the "purest", others may be. Now, should my ODO happen to flake out, one or the other would have to be restored. Constantly and compulsively looking into the tank would inevitably wear out my key and lock, and probably the hinge itself and I would have to find a giant cork in order to seal my tank from bird droppings. :hehehe


I am fairly certain the OP is fishing for restoring original operation at a budget price, similar to myself in my search for a master cylinder. My comments and query were merely an attempt to establish that depending on what exactly was "un-salvageable" the moto may operate just fine. No koan intended, and I reject any credit for unintended enlightenment..


If my understanding is incorrect, please accept my advanced apologies, and do correct my misstatements..


Now I just need someone to tell me that my handlebar buzz is caused by not having my variable resistor installed and operable so ChristopherGuzzi and I can both be on the hunt. :riding:

[Laitch]

I get it now, BrickMW. That sentence was an expression of a diagnosis. In itself, it wasn't enlightening but your explanation of its meaning is. Good luck with your buzz.

[Christopherguzzi]

Should have stated in my original post, hoping to find a used sending unit as new ones are damned spendy no matter where you get them.  Using a 12 volt power source and multimeter, I get 12 volts all the way to the connection outside of the sending unit but once inside the tank the connection stops.  If I bypass the connection and provide power directly to the sending unit I get 12 volts at the fuel pump leads.  The only thing I can think of is that the wires may have gotten pulled too hard at some point and/or have broken down in the resin where the wires attach to the sending unit.   :(

[Christopherguzzi]

By the way, BrickMW, I completely understood what you were asking.  To try to answer your inquiry, the fuel gauge windings are pretty much destroyed but the low fuel lights functions work.  As I don't have a fuel gauge on my bike, this is fine, but what is not fine is not having power to my fuel pump.

[Martin]

Wires can be replaced with new fuel resistant wires. I'm not sure where to get them but it has been done. You would have to remove the unit and replace the seals.
Regards Martin

[Christopherguzzi]

Wires can be replaced with new fuel resistant wires. I'm not sure where to get them but it has been done. You would have to remove the unit and replace the seals.
Regards Martin

Perhaps it could be done, but I would much prefer to just replace the faulty sending unit with a working used one at a reasonable price rather than trust my ability to effectively epoxy the wires in place while avoiding a fuel leak above the engine.

[rbm]

You have very little to loose by trying to replace the fuel pump wires with new ones.  It will take some skill and suitable soldering equipment to  ensure you get a solid electrical connection at the passthru connector, which might be a factor in your decision to replace rather than repair. If it works, then you will have saved several hundred dollars; if it fails you 'll end up buying a new one which was your original remediation plan.


Duck at kbikeparts.com has used senders for sale.  Also check ebay.de for tanksensor, tankanzrige, kraftstoff those types of words.

[Martin]

You are going have to remove the unit if you replace it any way, and replace the seal. So get some fuel resistant wire remove the unit and solder in the new wires with the appropriate connections. If you don't no how to solder surely you must know some one who could tackle the job, it really is not that hard. Are there any competent Brickers near you that can help, If you pay my return air fare I will do it for you. :dunno
Regards Martin.

[Laitch]

Duck at kbikeparts.com has used senders for sale. 

There's one advertised there right now—cheap.

[BrickMW]

There's one advertised there right now—cheap.

I tried to buy that one a few months ago.. It was NLA

An alternative to submersible wire might be to use the submersible vent hose to shield a bare copper wire inside the tank. Only the + lead would need shielding.

Knowing exactly where the break is would be better for coming up with the best remedy. Is it definitely in the epoxy portion coming through the assembly? Or just to either side? Inside / outside?

Sent from my SM-G935V using Tapatalk

[Christopherguzzi]

You are going have to remove the unit if you replace it any way, and replace the seal. So get some fuel resistant wire remove the unit and solder in the new wires with the appropriate connections. If you don't no how to solder surely you must know some one who could tackle the job, it really is not that hard. Are there any competent Brickers near you that can help, If you pay my return air fare I will do it for you. :dunno 
Regards Martin.

The sending unit (with new gasket) has already been removed from the bike.  Much easier to test and troubleshoot that way.  And no, I don't require assistance soldering a couple of wires in this case, so I'm afraid you're on your own for airfare Martin.   :neener:   That is unless you have some magical way of soldering wires inside the epoxy resin portion of the sending unit, as that's where the problem must be as the plug transmits 12 volts up to the sending unit before it enters the tank and 12 volts to the fuel pump leads after it enters the tank.  But if you would like to see the issue up close and personal, I'd be happy to show you, just send air fare and I'll be there in a jiffy. 
  :hehehe

As for used sending units, I've checked all the sites online and have made some inquiries, but nothing seems to be available at the moment.  So if nothing materializes soon, it looks like I'll be placing another order with Euromoto Electrics.  You win some ($20 original fit fuel pump from China) and lose some ($200 sending unit from Colorado).

Thanks for all the tips and advice folks. :2thumbup:

[Martin]

Would it be possible to use a Dremel or a cheap Dremel clone to carefully grind away enough epoxy to find the break. Harbour freight have rotary tool kits for $10.00 and $20.00. There are epoxies out there that you can use to cover over the repair.  https://www.harborfreight.com/power-tools/rotary-tools/heavy-duty-variable-speed-rotary-tool-kit-31-pc-68696.html
Regards Martin.

[rbm]

So, while you're waiting for a sender to become available and if you are willing to forego the low fuel indicator and fuel level sender, then use a marine grade liquid tight cable passthrough in place of the OEM connector.  Something like this:  https://www.amazon.com/Ancor-765002-Electrical-0-Gauge-39-56/dp/B000NI019O

• Use a Dremel to remove the sender assembly from the plate.
• Cut off the wires to the OEM passthrough connector but don't destroy its liquid sealing capability (alternatively, manufacture a new blank metal plate)
• Using the manufacturer's instructions, install the liquid tight cable passthrough, using a new 2-lead 18GA wire cable that is gas resistant.
• Connect the leads to provide power to the pump
• Install the tank connector on the other end

[BrickMW]

Now, should my ODO happen to flake out, one or the other would have to be restored.

And right on cue, my odometer stops turning...  :falldown:


Off to buy some pricey plastic.. unless I find a cork first.  :hehehe