Topic: Fuel line from petcock to carbs... is it supposed to fill completely with gas?

[Gorms]

I just put the petcock on my cafe tank and hooked it up the the carbs.  Its the petcock type with two screws that hold it to the tank.  It has two fuel outlets which after some testing it appears to have one for "on" and one for "reserve".  I connected these two with a Y connector.  When I turn on the petcock, gas kinda dribbles into the fuel line but does not fill it up.  When I run the bike with the petcock off and use some of the gas in the carb bowls and then turn the petcock on, the gas rushes in quickly but stops before the line can fill up.  Bike seems to run fine and does not get starved of gas but I haven't run it long enough to know for sure.  Is this normal?

[Gorms]

Could I have air trapped in the line/petcock?

[Spanner 1]

Completely normal to have air in the fuel lines when the bowls are full and no gas flowing down to the carbs.........IMHO.

[OldSchool_IsCool]

Normal.  Run it and the lines will "burp" through the bowl vents.

[TwoTired]

Air getting in the lines is normal.  If you use the stock tube routing, those bubbles will naturally rise to the fuel tap.  Inline filters and "creative" routing will trap bubbles in the lines.  And, this can be a fuel feed issue, particularly when the gas tank level is low, and the "head pressure" of the fuel in the lines is equal to or less than the air bubble back pressure attempting to get to the fuel tap.