XS Eleven Special fuel sending unit

[BrianB]

I searched around the forum and found no previous info about the fuel sending unit. This is for the 1980 XS1100SG. Mine does not work and I do not know if these are repairable. There is some signs of rust in the tank, not all that bad though. Would a good cleaning fix the sensor or should it be replaced. I already tried locating a replacement but have only came across one on Ebay that the seller can not say if it works or not.

[DiverRay]

Brian,
You should be able to clean it with "carb cleaner". I would then test it per the book with a DVM (Digital Volt Meter). If it tests good, keep looking along the wire path. If it fails the test, take a look at the connectors and wires on the unit itself.

[mro]

Not to be contrary

fuel sender in a special acts as a switch
can check with a cheep MM
Connect both leeds, one to each wire from sender
set to ohm (doing a continuity test)
with float arm raised = no reading on meter
float arm down and mm needle should peg to right
----
needle does not peg to right then there's an "open"
problem in sender or wireing
___
pegs to right
then temporarily connect the two wires that go to sender
idiot light comes on
then check sender wires and sender agin
wiggle/pull wires/raise/lower float arm(can work intermetintley)
----
light does not come on
check idiot light and associated wireing



mro

[BrianB]

Thanks for the help guy's. It is a rainy weekend coming so I will tear into this.

I believe this unit operates by a resistor changing Ohms to detect low fuel rather than a float. The '79 had a float but the '80 and '81 models had this other setup. I think a manual float would be best.

I had to run into work tonight and thought I had enough gas to get there and back no sweat. I ran out of gas a just barely made it to a station coasting in.

I tried switching the petcock to reserve but the tank was dry. I should have had more fuel in reserve. Maybe I have another issue as well now.

Well hope to get the light working this weekend. I do have the manual that describes the testing of this unit. I have tested all the other possible caues but the sender itself.

[AlanB]

Hi BrianB,

If there is no "extra" fuel in reserve (and you have read the tap correctly!) you have probably lost the "upstand" which projects into the tank from the fuel cock. This also has the tank filters incorporated, so better to fix it.

Unless a PO has removed 'em, they are probably sliding around in the bottom of the tank.

AlanB

[BrianB]

WOW, good point. I was thinking maybe the plumbing was wrong but I will certainly look into this. Going to take the tank off tonight after work and start looking into these two items.

Thanks for the help everone. Much appreciated.

Brian

[fredintoon]

That'll happen

Hi Brian,
the gas tap filter towers can and do fall out to lie loose inside the tank. But you'll never know it happened until your carbs plug up from unfiltered gas or you switch to reserve and find there ain't one.
Happened to me on my XS650 rig (same gas taps, same small gas tank but NO red light warning thingie) switched to reserve when the engine started to falter and there weren't any. I thought it was really doing well for mileage, but no, I'd just used up my reserve & not known it. I was way out of town too. With the rig I always travel with a 2 gallon jerrycan of gas so I could pour it in and carry on. Getting home I removed the tank and pulled the gas taps. No filters on either, shook the tank and heard them rattle, epoxied them back in.

[BrianB]

Do you gain access these tubes by removing the petcock?

[AlanB]

Hi BrianB,

Yes. They should be part of the petcock. The stick up into the tank an inch or so, so that the last bit of gas can't get out; that is your reserve.

It shouldn't matter what you do with the plumbing; if the cock is set to "on" the reserve fuel should stay in the tank.

AlanB

[BrianB]

Should I get a petcock rebuild kit before I start this or just use the same gasket and just glue that piece back on?

[BrianB]

It's Working

Tonight I dug into this and removed the Sensor from the tank. It had some residue on it but not that bad. I cleaned the metal surfaces with Carb cleaner. It cleaned up nice. I re-did the Ohm meter test described in the service manual and it worked as far as getting promising readings. I reinstalled the tank, added some gas ( not too much though ) and sure enough the light came on after about 1 minute. Added more gas and it went out. Drained a bit and it came back on so I am happy about that.

While doing the sensor, I also took out the petcocks to inspect them. Looks like one of the standoff tubes was not properly seated at some point. I cleaned them, inspected them and reinstalled them. Once reinstalled I did a test for On and Reserve since I was already changing Gas levels testing the Sensor. I found they both were good as far as reserve Gas staying in the tank while in the ON position. I did find on the Left side petcock that when it was in the ON position, gas only trickeled out while Reserve gave a good flow. Looks like I should probably tear into this.

[AlanB]

Hi BrianB,

Sounds like you are getting there!

Flow should be the same for both ON and RES...... like the other side, so it sounds like you need to get in there. You may find the obstruction under the front plate; It is sealed with an O-ring and is easy to deal with.

Does your SG still have the "Octopus" fitted? It is a vac-operated remote fuel valve, which should be bolted to the top of the carbs somewhere, and which leads to an amazingly complex arrangement of fuel lines.

If it is still there,I would suggest that you try a search for previous discussions of it, and that you consider removing it and simplifying the hoses.

Not everyone agrees, but I don't like 'em!

AlanB

[BrianB]

I do have the Octopuss still there. I will leave it unless at some other time I decide I do not need it and can simplify.

I took the tank off and rebuilt the Petcocks. Put gas back in and checked and everything flows good now. So I have accomplished my goals of making sure reserve fuel stays in while set to the ON position, and the low fuel sending light is working. I am totally excited about that.

Oh and I also replaced the Rubber Dampeners on the Tach and speedometer since the original ones were weathered. Not sure what else to do to this Bike. It is in awesome shape. And I did do the fluid check on the 2'nd and 3'rd gearbox. Reading that thread really makes you think.

I feel a very long relationship building with this bike.

[AlanB]

Hi BrianB,

Great news; Well done.

There are a lot of long-term owners on here..... kind of tells you something.......

AlanB

[fredintoon]

Wheredya find those?

Hi Brian B,
you mean the foam rings between the instrument and the outer can? Those things are scarcer than hen's teeth, what was your source for them please?