Good evening. Is there a mechanical fuel shut off valve that will fit the fuel tank so I can get rid of the vacuum valve? I think it's sticking and under load the carb is running out of fuel at high RPM. It then bogs down and stalls. It will restart after a few minutes but it seems to me there is no fuel as when you crack the throttle it just bogs down when trying to ride. Yet several times it has seems ok and that's what makes me think that valve is sticking because the NEW fuel filter looks like there is only a small amount of fuel in it. I would think if fuel was flowing properly and the carb was not running out of fuel the filter would look pretty full, no ? Fuel filter is new and carb is also new. Thank in advance,