Just got mine back from the shop with same issue. Needless to say I find myself looking at the petcock two or three times a day like I can see if somethings wrong with it. I replaced these gears 15T 19T 66T holder, pins and the case which had a chip out of it. I got most of the parts off ebay for less than $400. $1000 in labor (not the dealer) and had a new petcock put on.
There's a real good test here you can use when you have stuff apart (petcock off the bike):
http://www.valkyrieriders.com/shoptalk/petcock.htmWhen you can look down in there and see that little flap move, it give you a warm fuzzy feeling

...
Probably as good is to just turn off the gas while you're riding and see if you run out of gas (you have to go a little ways, it is not
instantaneous), coupled with running to reserve and observing that reserve works...
A petcock can go so bad that you can look at it and see that it is bad... gas can start leaking out of the weep hole on a bad petcock, unless
the weep hole is clogged and then gas runs down the vacuum line to cylinder number six. The weep hole was clogged on the leaky petcock
on my buddy Gary's new-to-him Valkyrie


It was leaking and blowing raw gas out the exhaust...
-Mike