I've been having problems with my 350f carbs running gas out of the overflows when filling empty carbs. Whenever the bike sat for a while or I ran it down to reserve, when I turned the gas back on it would dump gas out of the overflows, usually all 4. I've been carrying a long bolt under the seat to tap on the bowls to get them to stop. What was happening was when the floats got low enough, the needle would cock sideways in the seat, not allowing the float to come up. If there was always gas in there they were fine. I've had it apart a couple of times and polished everything up, no change. So I came up with the idea of building a cradle out of stiff wire that only lets the float go down so far. I've got them adjusted so the float will drop about 3/8" and stop. I fastened the wire to the screw that holds the seat retainer to the carb body. I had to grind a little off the float pivot because it contacted the screw head with the wire under there. If anyone tries this, be carefull where you run the wire and test fit the bowls to make sure it doesn't bend the wire up and shut off the needle valve on reassembly. Here's a couple pics. Works great. I ran it out of gas a couple times yesterday, when I turned it back on, no gushers. To make sure I wasn't restricting flow I rode about 4 miles into a 35mph headwind, took near wide open throttle to maintain 65. No starvation.