If the hardline is getting replaced, cut it about 1 inch away from the big inlet fitting, then use a 1" socket on the large fitting to get it out. Once out, use a 7/16" or 1/2" socket on the line fitting while holding the large one with a socket or wrench. The inverted flare can really be tight sometimes, and having the whole mess off the carb in a vise can really help. Using two sockets and wrenches works pretty good also. The new style green or copper colored steel brake lines bend pretty easy without the use of a bender if you want to make a new fuel line. Don't use rubber for the whole line, only a couple inches worth at most to join two pieces if you need it. The 250 has the exhaust manifold right under the intake, fuel leaks on the exhaust is not what you want. It could be 1/4" or 5/16" fuel line, they used both sizes, yours looks like it's the bigger one. The carburetor repair kits use teflon type material or paper type gaskets for the big inlet fitting, you don't see copper used anymore. The new stuff is much softer and conforms to the area with out as much force needed.
What year is your engine / carb ? I have a couple of 1969 - '70 250 carbs if you get into trouble with yours you can use.
