Originally Posted by mapbike
The tank has to vent for everything to work right, below is a link to what I would use.
The way I would do this is I would order the vent tube assembly, and when I got it I would find me a piece of small steel or brass tubing that the clear vent tube will fit snugly over, I would drill the hole in the gas cap so that the steel or brass tubing will just fit through the hole, I would braze the tubing into the gas cap myself but if you dont have access to a torch and the know how to braze I would simple go buy some JB Weld, clean all the parts very good with carb cleaner to remove any oil and then I would JB Weld the metal tube into the gas cap, let it cure over night slide the vent tube on the metal tube and walah.... you are venting that tank now.
You can also just put the metal tube into the gas cap like I described and then just run a 2 or 3inch piece of fuel tubing straight up off of it and vent it that way without buying the "fancy" little tank vent, my old dirt bikes vented with just a tube run up off the fuel cap, they didn't have anything on the end of them, so that will work just fine also.
I'd vent the gas cap before I went into the carb just to see if that will fix it, if not then I'd check the float level in the carb. no need to risk messing up a bowl gasket if you dont have to....
well i think the tank is vented. I actually had no problem earlier today when i took the bike out on a 20 mile ride. but near the end the gas did get sucked into the carb and the petcock wasnt letting out enough fuel. I did get time to drill out my old petcock straight thru and tested it on my other gas tank with water and it flowed out perfectly. I would replace the two petcocks but i feel like it wouldnt fix it. only way to know is to try lol so i think ill do that when i run out of gas. thought about adding an inline fuel shutoff but i feel the problm would still consist due to no back pressure to force the gas thru the tube and into the carb. wish they made a small fuel pump, that would be awesome!