Not a big deal its just if you replace the black rubber hose and put clear fuel lines on don't forget the brass tubing inside and throw it away. Easy to do.
But once the little brass tubing restrictors are in the clear fuel line you can see them and you would not accidentally throw them away.
The "restrictors " raise the fuel pressure coming out of the nozzles.
They are just small pieces of brass tubing (two pieces) that go between the carbs.
They are about 3/8 inch long and have a .155 OD and a .070 ID brass tube.
They are in two short pieces so that you can bend the tube to install it between the carbs.
They are not an exact thing . Easy to make yourself, if you accidentally threw yours away by mistake.
On a Roadstar Adventure.