Ca. Gas Tank Issues-Need Help

Hello guys,



I seem to have an issue with my gas tank, and I am only going to assume that it is my tank.



It is a California bike and has the odd vent type deal in the tank,(excuse my ignorance to what it is), some type of overflow or vapor catch system? Anyways, when I purchased the bike used, the tank was not overly rusty inside, but I did what I could to clean it out.

Installed a new Petcock, inline filter, new lines and fully cleaned the carb.



The bike runs great.....Until I get down to about a half a tank of gas, then it acts starved for fuel. This has only happened twice, and maybe it is coincidence, but when I top off the tank it runs fine until half a tank again.



Is there a dirt/rust issue that I did not handle with that vent/vapor/overflow deal in the tank? Or has this happened to anyone else? Filter is clean, Petcock screens are clean, I am just baffled.





Of course my next option is the Clarke TW tank, and then I have rust no more, my only concern is, will my bike be street legal with that tank?





Thanks in advance.



Brett.