I had a road bike once that suffered implosion of the fuel tank caused by a trapped breather....as the fuel went out the tank went in....but overnight !
I got it out with a bicycle pump, pumping air into the breather tube and petrol cap sealed off. Only took a few PSI .
7 years without the engine running ??? Whoever buys it should budget for a full engine rebuild, new oils. Filters and suspension oil change and seals In my opinion... Thats a lot of money on top of the price of the machine and then its still an 11 year old bike,
I would suggest before taking the carb to pieces that you clean the outside of the machine firstly. Second make sure you have a manual or pictures of the assembly of the said carb.
The jets are clearly shown in your 4th photo and the main jet has already been removed and on the table. They look like brass items if that helps.
