having crashed my mc21 I had to buy a second hand fuel tank , first ride out with new tank when i turned the engine off fuel started coming out around the cap , I pulled it apart to find that the bigger off the 2 pipes that come out the bottom off the tank has been welded up and if you blow air through the bigger hole by the cap it comes out inside the tank , I have since blocked this hole but am woried about causing fuel starvation , is the bigger hole by the cap meant to be a breather or should it breath only through the cap?