Don't know whats going on. I took the gas tank off and opened the petcock valve and fuel comes out fine, took the valve off and blew through it with the handle in the open position and it was clear, put it in the off position and couldn't blow throw it, installed it back on the tank and hooked the fuel line with inline filter back on the petcock valve, put the handle in the open position and fuel comes out enough to fill up a spray paint cap lid in a few seconds. When I blocked the end of the hose ( the end that would fit on the carb.) off with my thumb I expected it to fill up the line below the filter and fill the fuel filter. But no fuel was even in the bottom end of the hose. Is this a vacume problem? Funny thing is when its hooked up to the engine you can't see fuel in the filter but it runs with out running out of gas! Every once in a while the filter will have a very small amount of fuel visible in the bottom of it. I've tried removing the gas cap to see if it would fill up then but no change. This just doesn't look right to me and I don't want to brake down on a long ride. Any idea's??