My wife got me a bike for Christmas! 92 Vulcan 750. Guy we got it from said only problem was the float in the tab corroded into pieces clogging the fuel lines. I took off tank and removed petcock and saw the attached filter was the thing that corroded to pieces. I removed that and cleaned it all up added some has and turned the petcock on on, res, and prm, and no fuel would come out of the petcock. I could successfully blow air through the petcock inlet to outlet but gas wouldn't flow through. Gave up and just put it back on the bike and she about 30 secs of cranking the bike fired up and ran fine. Do these petcocks work off of vacuum? I'm used to just turning petcock on and seeing fuel flow freely. So are these petcocks vacuum activated? Also even when warm bike takes about 30-45 seconds to start then runs fine.