To be able to flow fuel through the VST to flush it, this is what I did. I disconnected the the return fuel line from the bottom of the fuel rail. This hose flows unused fuel back into the VST tank. I plugged the fitting where it attaches to the bottom of the fuel rail using a piece of 3/8 fuel hose with a 3/8 bolt inserted in to it to plug it up. I then used a can of carb cleaner with the small "straw" tube (like on WD40) to spray the carb cleaner up through the open drain line into the VST tank. When I had sprayed as much as I could, I then blew air through the return fuel line to flush the carb cleaner back out of the open drain line. When I did out came a lot of sediment which looked like rust. But I was told by a Suzuki guru, that it was oxidized fuel. At any rate, I did this process several times and now the engine runs like new. I hope I have made the process clear. If not, let me know if you have any questions. If you try this let me know how it turns out.