In have a 1985 suzi gs550e it starts but only

I'm going to guess that "pit ####" meant petcock :-) and yes they do "go bad" in a number of ways. There is a diaphragm inside which can crack over time. There is also a diaphragm return spring which may break (I've seen only one like that though). But most often, the use of fuel with ethanol in it will cause the breakdown of the plunger seal. When that happens, the petcock "leaks".... not externally but internally. The Maxim-X has a vacuum operated petcock which is supposed to only provide fuel to the carbs when set to PRI (prime) or when set to ON while the engine is running. When the engine is off, there should be no flow of fuel. But the damaged plunger seal allows fuel to flow from the gas tank to the carbs at all times, even when the engine isn't running. When you combine that leak with a leaky float valve, the result is usually a crankcase full of gasoline - clearly not good. If you'd like to know all there is to know about the XJ700X / XJ750X petcock, visit the following page on the Maximum Maxim-X web site:
Maximum MAXIM Resource for 1985 86 Yamaha 700 750 Maxim Models XJ700X...
There are also some helpful tips for rebuilding the petcock here:
http://www.maxim-x.com/pix/petcock/maxim-x_petcock_repair_tricks.txt
...with supporting pictures here:
Index of pix petcock
Hope that helps.

Get some carb cleaner and get that carb dismantled and sitting in that carb cleaner for a few hours. Drain that tank and run some approved gas tank cleaning agents all through it. Take the petcock off and check/clean out and usually - there'll be a filter type set up either attached to petcock or on inside of tank. The carb, the petcock and the tank - get them right before you even try to start it.

Large line is fuel, from tank to petcock. Large line from petcock to Carb. small line is vacumn from intake manifold to petcock (small spigot). suck on this line & make sure Gas comes through Large line to Carb.

Check carb workings,., float,slide or jet sticking in carb .,.,clean carb go from there.,

Reserve tube is usually set at a 1 gallon level in the tank, if you only added a gallon to an empty tank,I would fill the tank at least half full, If that doesn't fix the issue then replace the petcock, It's not a carb issue if it runs fine in reserve.

If I understand "the petcock was in prime position and it eventually quit dripping."
Prime = on
Sound like the needle rubber was hard and after a while they soften up enough to cut off the fuel.
Keep an eye on it and ride safe.
Ken

stored gasoline begins to deteriorate/lose octane/after only two weeks.drain fuel tank label and disconnect fuel lines at petcock,remove petcock from tank,clean fuel screen.re-assemble,check for supply to carbs. Honda's of that vintage have a seperate 'reserve' tank under the battery,which tends to collect all the 'crud',and must also be purged.trace your fuel lines to see if your unit is so equipped,

choke needs to be adjusted for current temp.

turn the petcock off when you park it and run the fuel out of the carb if it starts the next morning when you turn the gas valve on change the petcock