hi do i need a fuel vapour system, and if i do what does it do?? cheers ben

Never heard of one so I haven't!!

Rich

In a word - NO.

If you're running carb(s) then you shouldn't even need a fuel return line either although if you're building from scratch it's worth putting the pipe run in place in case you want move to an injection set-up later.

ok so is it not part of the fuel tank breather? and i dont intend on running fuel injection so could i get rid of it and if so do i take the pipe off at the sender unit? ben

fuel tank outlet -> fuel filter in -> fuel filter out -> mechanical fuel pump in -> fuel pump out -> carb in

Ditch anything else.

The tank wll need to be vented in some way. Either a vented filler cap or a second outlet (top of tank) with a one way valve or hose looped over and finishing below the bottom of the tank.