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Discussion Starter · #1 ·
Bear with me, I've just spent a few hours soaking up fuel vapors ...

The bike: 2001 EFI Softail Night Train (FXSTBI)

I'm having fuel gauge inaccuracy problems and need to adjust the float arm inside the tank. The fuel gauge sending unit and arm are somewhat "Z" shaped as depicted in the 2001 shop manual. I get about 130 miles before the tank reads empty, after topping off. The gauge itself does work, reads full and drops as the fuel is consumed.

Here's where I've gone stupid.

My low fuel lamp is lit and the gauge is below E but there's approximately 2 gallons of fuel in the tank. I know as it was siphoned out and put back in. This tells me that the float needs to be adjusted but for the love of God, I can't tell if it needs to go UP or DOWN. I would assume that bending it DOWN would lower it into the fuel further, raising the "float" resulting in a higher reading on the gauge.

If it were that easy. I've bent the rod both ways and haven't gotten any further in changing the gauge reading.

So, which way should I be bending the arm, UP to raise the float or DOWN to submerse it further?

Also, what would a bad or faulty fuel gauge sending unit do?

For what it's worth. It must have been this way for a long time. The previous owner told me the tank was 3.5 gallons. I knew better. Funny thing is that it takes about 3.2 gallons to top it off when the gauge reads empty. This tells me it's been way off for a long time.

Thanks in advance.
 

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first off the (idiot light cousin) on your tank is probably the same prod. run as my 02 (Itt'l lie about every other gallon hitting empty at +- 1.5-.9) bendin the arm down should cause it to register more fuel(as it will cause the reahostat(not spelled right) to read more input voltage, I THINK this should be the same on hd as any car???good luck ride hard cb
 

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Yep, bending it so the float is lower should do the trick. When the float is floating, the contact on the rheostat would be higher, showing more fuel.
An important thing to also remember is to replace the plastic grommets around the screws. You don't want the screws shorting the sending unit.
 

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Agreed, bend it down. I bent mine 3/4" longer and it's still not enough. 1/2 full is about right, but I've still got a gallon and a half when it hits E. 5 gallon tank also.
 

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Discussion Starter · #5 ·
Thanks for the feedback. It wasn't that difficult, even though I was high on gas fumes ...

I measured the fuel going into the tank at exactly 2.5 gallons and adjusted the needle for 1/2 tank. When done, I topped it off with 2.25 gallons, threw some wax on the tank and called it a job done.

The only thing that puzzles me is how it got this way in the first place. My float arm is "Z" shaped and was not all that easy to compress. Being off by more than 2 gallons from the factory is what bothers me.
 
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