Why do people like to replace the stock petcock?

[Toad Rider]

I'm sure this has been discussed here a 1000 times.

I got a '96 GS500E about a month ago.  I'm the third owner.  The first owner replaced the stock petcock with one that is just on/off.  The guy I bought it from said that there were a lot of problems with the stock petcock.

What were those problems, and what is the advantage of not having the vacuum line connection?

[spc]

Ummmm...basically the stock petcock sucks................... the diaphragm tears easily, essentially rendering the vacuum based ON position useless and causing the bike to need to be run on PRI.  Replacing it just simplifies  the fuel hose routing and beautifies it a little

[Jughead]

Yeap it Sucks.You have All of thse Hoses to Crack.Replacement Fuel Line that Size is only Available from Suzuki although Regular Fuel Line Will work it hardens within a few Months.With a Pingel or Equivalent,One Line and a Few Vaccum caps and thats it.

[spc]

I gotta get around to gettin one   The Clear Blue line from partsunlimited works just fine for me as long as you cinch it down good

[dgyver]

Not only the diaphram fails over time but there is a small rubber flap type check valve in the vacuum line of the valve that fails as well. All of the valves that I have converted to no-vacuum has had a check valve that turned to goo and all but sealed the vacuum line closed.

Running in Prime is really not the best solution. The Prime port is about 1/8" dia and the others are about 3/16" dia. This still limits fuel supply.

[Toad Rider]

Are there any disadvantages to not having it?

[dgyver]

Better make sure you shut off the valve when not in use and that the float needles seat properly. If you do not turn it off and your float needles leak, gas will flood out of the carbs, possibly into the motor. I used to never shut the fuel on my race bike and did not have a problem.

[cosmiccharlie]

So where can I buy the better version?

[LostDog]

Check this out:
http://cgi.stanford.edu/~sanjayd/gs500/Upgrades/Petcock

And this:
http://gstwins.com/gsboard/index.php?topic=17129.0