I don't know if anyone already done this?

But can the fuel tank from a carburettor system favorit/felicia, be fitted to a fuel injection system favorit/felicia, to increase overall fuel capacity?

It looks like it is a straight swap with just a few modifications to fuel lines, relocation of fuel filter,and change the fuel level sender/(fuel pump-on injection engines)

Looks like carburettor fuel tanks are rare though.

I think the same but why bother since the consumption is lower. 

The answer is in the thread title.

I was meaning just the tank, not the whole fuel system.

If anything would be different I think it would be the diameter of the sender unit apature. 

If it did fit, It should increase fuel capacity from around 42liters to 47liters, giving about 50 miles extra, from a full tank of fuel, for fuel injection engines.

Just seeing if someone else had done it, to see if it was possible, and to gauge how hard / easy a job it would be.

I think the hardest part would be sourcing a fuel tank from a carburettor model.

I think that volume of fuel pump is main reason for lower tank volume. So you'd probably need some external fuel pump to increase volume noticeably.

But why? I was able to get 700km from a single tank in my 1.3MPI.