gas tank low fuel light

[tjtrahan]

My 1980 xs1100 low fuel light seems to work when it wants to. Took the tank off the electric lines are good and have continuity thru them. I f I unplug the tank and cross the wires to the bike the light in the dash lights up. Is there a way to clean this unit does it have a float arm or just resistance. Last time I took it for a drive made it home chugging on the fumes,dont wnt to try that again. T.J.

[Bill__Woods]

hi,
the fuel level sensor is a thermistor. It changes resistance with temp. I will check the service manual and see what the specs are later tonight, after my ride. If there is buildup on it i would clean it all off.
good luck

[JP]

Only on a Special. On a standard it's a float mechanism. And before you ask, no it's not interchangeable.

[TopCatGr58]

Re: gas tank low fuel light

Originally posted by tjtrahan
My 1980 xs1100 low fuel light seems to work when it wants to. Took the tank off the electric lines are good and have continuity thru them. I f I unplug the tank and cross the wires to the bike the light in the dash lights up. Is there a way to clean this unit does it have a float arm or just resistance. Last time I took it for a drive made it home chugging on the fumes,dont wnt to try that again. T.J.

Well, according to the manual, if you only have a warning light, then you have a Special with just a thermistor type sending unit; if you have an actual fuel gauge, then you have the moving float type.

The manual states in the wires from the tach housing inside the headlight housing you should get 12 volts from brown wire to ground, and from the connector side of the sending unit plug, 12 volts from the green wire to ground.

On the sending unit, connect Ohmeter to green and black wires of sending unit, should read 1500 plus/minus 100 ohms at 77 degrees F. If not, needs to be replaced, not serviceable, apparently the gas keeps the unit cool keeps a switch mechanism open so the circuit to the light is broken, but when the gas goes down, it heats up/expands something that makes contact with the switch and completes the ground turning on the light!?!?

Tj, were you running on reserve from the beginning?? Most folks dont' hit reserve until after their light comes on, and then they have 10-20 miles yet to go, so if you were down to fumes then it sounds like you missed the reserve-were running on it from the beginning!?!?

[tjtrahan]

I wonder if the 95 Degree Sun the day before could have anything to do with it. The bike sat out in the sun all day, tank was so hot could hardly touch it.at the endof the day i put it in the shade. T.J.