What is the open position for the fuel petcock...parallell to the ground? Or is is it perpendicular...basically which way is ON, OFF, RESERVE?

It's the fuel petcock switch. Here are some pictures of it: https://www.google.ca/search?q=2004+kawasaki+vulcan+1500+fuel+petcock

Fuel petcock valves are common on motorcycles which don't have a dedicated fuel level gauge. They are use to turn the fuel tank "on" or "off", and they also have a "reserve" position which taps into a section of the fuel tank which contains reserve fuel to allow you to make it back to a gas station should you run out of fuel in the "on" position.

It sounds like you have an aftermarket petcock on the bike. I am not familiar with a Harley petcock that has a round knob but then maybe just the knob is an add-on. In 1996, Harley went to a vacuum operated petcock, one that gives lots of problems. I cannot tell you which way is reserve on your petcock. The only way to tell for sure is to pull the petcock out. You'll see a plastic strainer on top of the petcock. Inside the strainer, there is a tube that runs approximately half way up the strainer. Select a position on the petcock valve and blow through the petcock. When you feel the air come out of this tube, this is the "ON" postilion. Right beside this tube inside the strainer is another hole directly into the petcock. Find the position that allows for air to pass through this hole and you've found the "reserve" position. The remaining position should be "off".

Good Luck
Steve

The reserve position alows fuel from the bottom of the tank to flow. It sounds like you have crud/water/blockage in that fuel path. Turn the fuel off. Remove the fuel line at the tank. Place a long fuel line on the petcock to drain the fuel in a can. Place the fuel on the reserve position and watch how much fuel flow you have. Now blow back through the line while on reserve to clear the crud and again look at flow. This will let you know if you neeg to remove petcock and clean filter screen
inside tank.
Good Luck

To see what is wrong you will have to drain the tank and take off the fuel tank outlet(filter assembly). What you should see is a tube sticking up with a fuel filter over it. The tube allows the fuel to enter the carburetor down to that level , when the fuel petcock is in the ON position. When you switch to RESERVE the rest of the fuel flows down through a hole at the base of the fuel petcock. If the tube is missing from the fuel tank outlet(filter assembly) or/and the actual fuel petcock switch (sometimes a separate part )you will not have RESERVE. Another way you have no RESERVE is if you have a leaking four hole washer in your fuel selector. This allows the fuel to flow from RESERVE to ON inside the selector valve(gas leaking in petcock but not escaping outside petcock). "Honda" has all sizes of 4 hole washers available, but , the assembly may not be designed to be taken apart and reassembled. In either case you may end up having to buy an assembly to fix your problem.

Either the intake tube on your fuel petcock has fallen off, Your petcock has worn out and is allowing fuel from the reserve position to leak into the on position hole , or you had the lever in the wrong position. If you had the petcock turned to the correct positions, the you may want to drain the tank and remove the pet **** for inspection. If the fuel inlet tube for the ON position has fallen off, you in effect, have no reserve. If the petcock is worn out you will need to replace it so it will work the way it is supposed to.

problem is probably the fuel petcock try this test disconnect the fuel line and get a good length of clear line enough to reach a container hook it up to the petcock and turn the petcock in the on position and observe the flow of fuel to see if it is flowing freely try this in the on and the reserve position.
if it id restricted remove the petcock and clean the obstruction of rebuild or replace it.

You have fuel injection? If so, no reserve AFAIK. In the carb version, the gastank fuel petcock is the fuel reserve switch, the lever's normal position is straight down, reserve position is straight up, off is sideways.

When you switch to the Reserve position, fuel is drawn from the bottom of the tank (vs. from a tube sticking up about 2" from the bottom, when in the On position). Something is either blocking the flow of fuel into the Reserve inlet on the petcock, or the rubber seal inside the petcock is coming apart and blocking the flow of fuel. Either way, drain all of the gasoline from the tank and remove the petcock so you can see what's going on in there.

The valve is open when the lever and valve are parallel. Generally that is down. When the lever is pointing across the valve it is closed. Think T vs. I. If the lever and valve cross it's closed, if they go the same way it's open.

That applies to a two position valve, if your Bayou has a reserve postion it could be different. That would be three positions and across one way would be open, down would be reserve, and across the other way would be closed. Should be marked on the petcock if that is the case.