Intermittent starvation

[Powerman]

I don't trust my Valkyrie anymore. After lots of years,but not many miles my '97 tourer left me stranded twice.  She was running fine for about 20 miles and all of a sudden she started sputtering. Seemed odd, but maybe out of fuel so I fueled up, and stopped for lunch.  Ran fine for a few mile then stared sputtering again, choked it and it ran better.  Backed off the choke after a minute and it ran for a while.  This pattern continued.  Tried to limp home, Dangerous.  Got progressively worse.  Gave up and called a cab.  Had to pick up the old girl with my trailer.
Had the carbs cleaned, same problem after 15 miles or so. I didn't find any kinked fuel lines, took the petcock apart, seems fine, but I'm no expert, no holes or tears.  She just doesn't run right consistently.
I got her new in '97, trigger wheel, two brothers canisters (cut down after dragging them through too many corners) only 14k mi. Any known problems or suggestions on what could be my issue or who I can take it to in Southern California?
Thanks

[Hook#3287]

Try riding with the fuel cap open.  You can take the key out, after opening the cap, by pushing down on the mating ring of the cap.

Just close the cap w/o pushing it all the way in.

Your vent tube could be clogged.

[Powerman]

I'll try that.  I did open the cap while on the side of the road, hoping that would flood fuel back to the carbs, but that didn't happen.

[gordonv]

Common problems.

Tank was removed, and when placed back, the vent tube was kink/plugged (open gas cap. Usually a problem at around 1/2 tank of fuel).

Petcock not on the proper setting (you need to feel that indent as the ball drops into position). Try changing between On and Reserve.

Petcock failure. Vacuum line, diaphram.

Fuel line messed with. Replace to stock, no fuel filter.

A 20 year bike with only 14K miles. Not been run too often. Add 1/2 can of Berryman B12 to 1/2 a tank of fresh fuel. Low speed, high gear (low RPM). 50-100 miles. Let it sit. Then repeat.

What has recently been done to your bike?

[Dusty]

A cracked or leaking vacuum line that goes to the fuel petcock  may not allow the petcock to open fully. Have heard of this before , similar symptoms and the solution was a new line to the fuel petcock.

Dusty

[Powerman]

Nothing new had been done to the bike when I had the problem the first time.  Stock fuel line, changing between on and reserve didn't help.  I'll check the tank vent tube.  Any easy way to test vacuum on the petcock?  I'll do the berryman treatment too.

[Blackduck]

Poor boy method on the petcock, remove the fuel line Hook any hose you have to hand that will fit over the petcock and run to a container. Remove vacuum line from #6 carb.
With the petcock in the on position take a suck on the vacuum line, fuel should flow and stop when you release the suction.
My bet is on the tank vent line.

[Hook#3287]

I'll try that.  I did open the cap while on the side of the road, hoping that would flood fuel back to the carbs, but that didn't happen.

even after opening the cap after fuel starvation, you'd need a vacuum draw on the petcock and time for the carb bowls to fill.

When that happened to me from a inline fuel filter, I almost drained the battery restarting.  I was somewhat impatient    I removed the filter the next day, bought a new battery.