I have decided to use my old tank but my key does not open the tank any more  question #1 how can i get the cap off without using C-4 ? #2 I took my carbs apart and in the bottom of one of the float bowl I found a tapered piece of brass with a hole through it. The size of the piece is the size of a bic pen head i think the carbs have a jet kit but not shure of what type ( the needles are silver in color without any markings ) i was thinking this is some type of air or gas restrictor does anybody have any ideas thanks anthony I will owe you guys alot of beer when i am old enough to but it LOL

You can drill out the lock on the cap, I did mine and I can still use the key.. just any key will work 

There is a way to remove the cap without a key. PM me and I can tell you how.