I recent inherited this 2002 Metro with 200 miles on it that was a pit bike for drag racing and had been in a race trailer out of sight since 2005 and need to get this on the road asap, registration/insurance all complete just this one problem, the tank. I have to round trip about 19 miles a day on a bike right now as I was in an accident last month involved in a rollover and the ride with broken ribs is not great. I've already done all the preliminary, rebuilt the carb/plug/fuel lines/fuel pump and filter and oil, ect. Right now I'm stuck on a really small budget and can't afford to replace this tank but have been working on it small amounts at a time and grabbed a new pump today so I need to try and see if I can revive this tank, it was stored with very little fuel in it and after cleaning it with soda/vinegar mix initially then some tank cleaner and BB's with the good old shake and recently put some gas in it to shake around as well and help clear out what else might still be floating. I've ran hot water through it in intervals of 45mins to an hour and it doesn't flush up debris anymore and I've repeated the steps over 3 days and the tank internally looks ok from what I can see with a light but then I noticed no fluid was coming out the stem on the bottom so I probed it with some guitar string I had laying around and it penetrates about 4 inches and at first had some older gunk on it but not much. Today I pumped in some air with my compressor through the stem and some clearly gets into the tank in an attempt to possibly blow out what might be in the way but without an internal diagram I have no idea if there is a baffle down there blocking the way and or what/how the stem functions like maybe a hidden 45* down there somewhere that stops the string from going further in so I can't totally clear it that way. Under pressure with the cap on it pressurizes and I can hear air entering and can visibly see bubbles inside when observing with the cap off but nothing exits back through the stem like there is a possible gate or something which would make no sense and even attempting to suck fluid back through the stem as the pump would, nothing, yet air goes in. I'm stumped and need to get this stem cleared and even if I have to constantly replace fuel filters right now until its cleared to the maximum extent it can be I need to get this running so I can continue to work on it. Next step and only thing I can think of is repeat again and maybe use some nuts or something else with more weight than the BB's but I feel it's going to be fruitless still without understanding how this specific internal system works because its obviously not just a straight shot up into the tank from the stem and it doesn't have any type of vacuum system in place being an 02 model and really seems like it should be straight forward and what I'm used to with cars/trucks but this little thing is being a major PITA to figure out.