+1 to all theory's about the fuel to the fuel pump for "real life conditions"
Dirt bikes used to feature a vented gas cap with a tube. Plug that puppy up with mud or crimp the tube up by the handlebar, and you'll chase your tail the rest of the day trying to figure out why it does the same thing as yours. If your luck is good, you'll figure it out. If bad, it'll cure itself, only to happen another time on the trail.
I suggest I heard/read somewhere on here that the fuel pump (line) pressure is something way low like 4 or 5 psi. If thats the case, you can imagine it wouldn't take much fluid head to negate that flow of gravity if your can is not vented to provide good drained (SUCKED) flow.
I don't know too much about this stuff though. Culd have saved everyone a bunch of time by just saying +1?
GeeVee
