78 1100 gas gauge

[ticofruit]

I found a real clean 11 in Oklahoma on e-bay after selling my 80 model SG in 1997 to buy a sportbike- big mistake! Everything works except the gas gauge. Does anyone have advice for tracking down the problem? Thanks from Ticofruit!!

[wildbill]

Have you taken the seat off and checked the connecter where they plug together?Check in the service manual there is a section on this in the book.If the sender unit is bad I have one that I have taken out of a 78E tank that worked before I took it out but I can`t use it now because I have a special tank on the bike now.Check the other things first the cause is somewhere in there if not I have a sender unit.Hope this helps.

[xssiveone]

There is a voltage regulator mounted in the back of the gauge. You don't have to take the gauge apart, just remove it from it's mounting. Check to ensure that you have voltage coming from it. The manual describes the proper procedure.

[skids]

Re: 78 1100 gas gauge

The gage should return just below the empty mark with the key off. If it shows anything else, the bi-metalic element may be broken. The current supply from the gage to the float should be something like 7 volts. The float unit is a variable resistor (sorry, I don't have a manual...8 ohms to 85 ohms???)

Originally posted by ticofruit
I found a real clean 11 in Oklahoma on e-bay after selling my 80 model SG in 1997 to buy a sportbike- big mistake! Everything works except the gas gauge. Does anyone have advice for tracking down the problem? Thanks from Ticofruit!!

[ticofruit]

Thanks for the help! The gauge comes and goes on and off mostly off.Likely the sending unit? Thanks !! Ticofruit

[scalded dog]

I have the same problem with my 79 standard, the gauge only works sometimes, when the tank is full, the bike had sat about 4 yrs, it had a lot of junk in the tank, the sending unit probably needs replacing, but I get about 120 miles on a tank, then I have reserve. so I just turn back the milage counter when I fill up. 16,000 miles later I still havn't run out of gas, but am getting ready to put the replacement gauge in the tank. LOL. Later 'Dog

[mastan]

I had the same problem with my 78. I found a fuel guage regulator on e-bay and that fixed it. Its mounted inside the tach housing.
Mark Stanton
78xs11

[skids]

If it registers the correct amount of fuel when it is working, you might have a dead spot in the float unit. There is a tang that makes contact on some resistor windings. Blane Hoopes said that he bent the tang a little to make the contact better. It is probably gunked-up with gasoline tars, rust, or other. I suggest that you test the voltage supply when it is not registering on the gage before you tear into the gas tank, to see if it is maybe a corroded clip or a bad gage volt regulator.

Originally posted by ticofruit
Thanks for the help! The gauge comes and goes on and off mostly off.Likely the sending unit? Thanks !! Ticofruit

[strom]

A friend has a 79 standard, and his "regulator" thingie thats all covered in plastic within the speedo unit fried. Any ideas what the thingie does, or can it be replaced with something else?

LP

[skids]

It regulates the voltage down to 7 volts(?) from whatever volts is supplied (up to 14.5 volts). You might be able to find an integrated circuit VR. I found one that outputs .5 volt higher than normal and as a result, my gage always read too high.

Originally posted by strom
A friend has a 79 standard, and his "regulator" thingie thats all covered in plastic within the speedo unit fried. Any ideas what the thingie does, or can it be replaced with something else?

LP

[strom]

Voltage varies there depending on the fuel level, or is it a consistent 7V?

LP

[skids]

Voltage supplied from the gage's volt regulator is constant. The variable resistance from the sending unit in the tank causes the amount of amps to vary to the gage. The gage itself is a bimetalic element that is wrapped in toaster coils that heat the element....the more the heat, the more the deflection of element and the needle. PS, the element is prone to breakage near its base.

Originally posted by strom
Voltage varies there depending on the fuel level, or is it a consistent 7V?

LP

[prometheus578]

Can't 'member if I soldered mine or used crazy glue, but that bimetal element is fixable. Make sure you readjust the setting when your work is done. What I mean is.... my gauge now works, but bike would run outta fuel before the needle hits the empty mark. Get the tank to the point where it runs outta fuel, then adjust the needle in the gauge to the empty mark and tighten the assembly down.
(been a lotta years, can't recall what it all looks like in there)

[skids]

Yes...I did a similar repair job. Full was off scale and bone-dry (where did that awful phrase come from?) was a quarter on the gage.

Originally posted by prometheus578
Can't 'member if I soldered mine or used crazy glue, but that bimetal element is fixable. Make sure you readjust the setting when your work is done. What I mean is.... my gauge now works, but bike would run outta fuel before the needle hits the empty mark. Get the tank to the point where it runs outta fuel, then adjust the needle in the gauge to the empty mark and tighten the assembly down.
(been a lotta years, can't recall what it all looks like in there)

[LoHo]

Mine's always been the other way around...brim-full registers at 3/4 full, and reserve is needed just below "E"...I didn't know I could adjust it. I've always been reluctant to tear into my bike, as everything worked well, but now, the gloves are off! (So are the carbs!)