Here's a problem I've never been able to figure out. I have a transparent fuel filter on my petcock which then splits to the front and rear carb fuel lines. Everytime I hop on the hwy (75-80mph) to work I notice the level in the fuel filter drop slowly. By the time I get off the hwy the bike's sputtering, the filter's empty. I have to pull over, remove the filter, let fuel pour freely from the tank into the filter to fill it and then plug it back onto the petcock. Then I'm set for another 10 minutes or so. Sometimes it empties again, & sometimes not. The weird thing is that it never does it @ night on the way home. In fact, I drove back one night from Daytona to Orlando & the bike was fine. At first I thought it was pressure-lock but I tried riding with the gas cap off and it still does it. When the filter empties out (whether the gas cap is on or off!) you can actually see NO gas dripping from the tank. As if there were no more gas!!! But as soon as I pull off the filter the fuel pours out rapidly from the petcock. That's the only way I can refill it too - by letting the fuel 'fall' into the filter. If I actually connect it to the petcock nipple it won't refill. BTW, it seems that once I've done it 1 or 2 times it doesn't empty anymore. She runs great. Not sure what the secretive 'variable' is. Is it a matter of warm-up time? Maybe the hose seals need to heat up or expand? Is it a driving pattern that I do while going to work but not when coming back? Is it air seeping into the system? I've thought of everything! Thanks for taking the time time to read this.