Am I doin it right?

[stompy]

ok so when I get low on gas (fuel selector in pri) the bike runs a little rough so I put it in res but VERY shortly after the bike dies. and wont start until I put more gas in it. also what is the third posistion on the selector for. BTW. I bought the bike used (97 gs500)

[Ry_Guy]

The tank is designed poorly. You will "run out" of gas before using all the actual gas in the tank, regardless of what the fuel selector is at. Also, it's not good for the GS to run it out of gas. Try to keep it at least 1/4 tank full at all times.

[beRto]

ok so when I get low on gas (fuel selector in pri) the bike runs a little rough so I put it in res but VERY shortly after the bike dies. and wont start until I put more gas in it. also what is the third posistion on the selector for. BTW. I bought the bike used (97 gs500)

PRI draws fuel from the same outlet as RES. For this reason, if you are running in PRI you do not have any reserve fuel.

You should run the bike in the ON position (this is the third position that you were asking about). If you use ON, you can switch to RES when you run out of fuel in the main tank. There should be about 1 gallon of extra fuel in the RES position (~50 miles).

PRI is used whenever the bike has been sitting for a long time or if you run the gas tank completely dry. The PRI setting allows for fuel to flow to the carbs even though the engine is off (ie. "priming").

This figure may help to explain how the petcock works:

[Chokstick]

PRI draws fuel from the same outlet as RES. For this reason, if you are running in PRI you do not have any reserve fuel.

You should run the bike in the ON position (this is the third position that you were asking about). If you use ON, you can switch to RES when you run out of fuel in the main tank. There should be about 1 gallon of extra fuel in the RES position (~50 miles).

PRI is used whenever the bike has been sitting for a long time or if you run the gas tank completely dry. The PRI setting allows for fuel to flow to the carbs even though the engine is off (ie. "priming").

This figure may help to explain how the petcock works:

Awesome explanation!!

[beRto]

Thanks! You inspired me to take the time to add this info to the wiki:
http://cgi.stanford.edu/~sanjayd/gs500/Upgrades/Petcock

[Affschnozel]

ok so when I get low on gas (fuel selector in pri) the bike runs a little rough so I put it in res but VERY shortly after the bike dies. and wont start until I put more gas in it. also what is the third posistion on the selector for. BTW. I bought the bike used (97 gs500)

Make sure your gas lines aren't mixed up, there are two coming out of the tank,one is the main ( ON position),other is the reserve.

Ran dry couple of times until I realized that I switched between them 

Ooops, you said you ran it on Pri .....never mind 

[stompy]

in other words I anint doin it right.  thanks for the info BIG HELP!!!!!

[ben2go]

Check your hose routing.   http://cgi.stanford.edu/~sanjayd/gs500/Main/HoseRouting

Here's how to mod your petcock for non vacuum use.I do the mod.Contact me for details. http://gstwins.com/gsboard/index.php?topic=19363.0

Here's a cheap alternative. http://gstwins.com/gsboard/index.php?topic=36958.0