thermistor check

[fredintoon]

My thermistor recently quit, leading me to embarrass myself about saying I'd have to clean the carbs when the bike was running out of gas.
Here's what the search button says:-
" The Specials use a thermistor, a thermal resistor. When it is submerged in liquid, the gauge light remains off, when out of the liquid, the light should go on. I have had them go bad before. My test was to try another in it's place."
Am I right in thinking that this means the thermistor will not conduct power when it's wet with gas but will conduct power when it dries out?
My Ohm meter shows infinite resistance on mine, wet or dry, so it's hooped, right?
I got a replacement and it does that too.
Seems I'll be real careful watching the odometer until I can arrange to get #3.

[TopCatGr58]

Hey Fred,

My understanding is that the thermistor does not conduct current when it's COOL which is when it's submerged in fuel. When it gets dry, then it can heat up and that's when it conducts current to turn the fuel light on.

So...your replacement unit may be good, but you probably need to connect it to a power supply for a little while and see if it heats up, and then you could retest the resistance...or just put a bulb inline with it and see if it lights up after a short while connected to power.

T.C.

[fredintoon]

Hey Fred,
My understanding is that the thermistor does not conduct current when it's COOL which is when it's submerged in fuel. When it gets dry, then it can heat up and that's when it conducts current to turn the fuel light on. - - -

Hi TC,
the problem was Mr. Stupid not knowing quite how it worked.
Use the multimeter's high Ohm range and there is a small reading.
Wait a half-minute for the unit to warm up and the red light comes on.