This is what happening to me very early this morning...
My odometer showed 205 and I have the fuel arrow pointing downward opposite to the REV indicator. Then my bike choking and come to a complete stop. I switch the arrow pointing upward (in line with the REV) and restart the bike. The bike ran for less than a mile and died. No matter which direction I turn the arrow, the bike refuse to start again...
I pushed it to a gas stop (about a mile away) and refuel. At this time, I switch the arrow showing downward again and restart the bike.  Bingo, the bike runs fine, then.

Lesson learn: What exactly is the ON position using the arrow as a point of reference for the GS500 ?  I am still confused about this.  Next is the question why on RESERVE (let assume this is the case), the bike can go only less than a mile ?  I thought the reserve should hold about .6 gallon which will allow me to go at least 10 or more miles...

Does any one have something to share regarding this problem ?

'On' is the vacuum actuated selection that utilizes the upper half to almost the entire tank depending on how Suzuki manufactured your specific tank.
It just seems to depend on each individual tank.

I'm doing range testing again and I have the stock fuel selector pointing to 'on' and the hoses hooked back up correctly on a CA-spec '94. Tripmeter reading 141.9 and I have a 12.1 mile commute home.

Do you know if the tank has every been off or fuel lines replaced? If so it sounds like your fuel lines are crossed which means you have no reserve and you ran the tank dry. Very easy thing to do. I'm speaking from experience. :guns:  I have a 91gs and I believe my reserve is .9 gallons or very close to that. Somebody can confirm that.

No. It's impossible that the line got switched because just over a month ago when the gas ran out around 240 (on tripmeter), I turned the petcock (arrow) pointing upward to where the REV indicator and restarted the bike and ran it for about 5 miles or so to a gas station.  Since I didn't have the petcock position being reversed then, it's a puzzle to me now that I have this problem today...

Could it be some water left in the reserve area of the tank ?  Mine is a 2002 model with 5K miles purchased in April, 2003 ?

Note: When I refueled the tank today, I noticed that it took up to about 4.6-4.7 gallons to fill up where the gas just kind of touching the base of the
tank's opening. I also know that the tank capacity is 5 gallons (CA model), therefore it seems odd that I ran out of gas somewhere between 4.6-4.7 gallons ?  Another mist. of the GS500 perhaps ?

Don't count on using the last .3-.4 gallons of fuel.  If you got down to .3 gallons you're the newest recipient of the "Bone Dry" award.  The real question is why you were able to use so much of your fuel in the ON position.

Question:  You keep saying that the REV (RES?) position is UP on your bike.  On my '96 and '99 the RES position is FORWARD, and the UP position is PRI.  What year is your bike?

mine is 02 model with over 5K miles on. I agree with you that why I was able to run up to 4.6 gallon before reaching the RES.

The petcock on my bike show topdown as  RES  PRI  Blank (assume ON position).  Also there is a mark saying Fuel but you can't turn the arrow to point to this mark.

See if you can understand my problem.

Thanks

Just to double-check:  your fuel switch is NOT labeled like this?



(My thumb is near the ON label, my finger is near the PRI label.)

EDIT: Changed link from sisna.com to bbburma.net

No. My fuel petcock shows in reverse of yours. Let me try to depict it here:


Top:        (---RES---))))
              (     ||     ))))
Mid:         (     ||     PRI
              (     ||     ))))
Bot:         (     \/ -----------> this is the arrow shows on top of the knop.
                  Blank

Assume that you look straight to the petcock where the bike is on its stand. You see, the RES shows on top, then the PRI is to its right 1/4 turn and the Blank (ON) is at the bottom center.  The arrow in this picture is a
black rubber knop which you can turn in 3 positions only. That is pointing it to the RES, the PRI or the Blank where I assume this is the ON position and in this position, the tripmeter showed 205 miles this morning when the bike stopped running.  Then I turn the arrow upward to the RES and the bike could only go for about less than a mile before it stopped dead.
So, I pushed the bike to the gas station and refueled and noticed that it took 4.67 gallons when the gas touches the base of the tank's opening. I could fill in a little more so that the gas will come up to file the tank's hole, but I think this would not be more than .2 of a gallon.