NEEDLE VALVE 1.5

This is for a Mikuni carburetor with a very specific model number. Fuel pumps are found in almost all fuel systems, and they can be external or internal to the carburetor. Gravity feed is the only other option. While the size of the orifice does affect fuel flow, there are many other factors that influence fuel flow just as much as or more than the size of this set. The only correct response is that there isn't enough information in your question to determine whether it's the right one for you.