78 honda express carb question (1 reply)

I'm rather new at this but I've gone through the basics and got my Express running well and am wanting to get a bit more out of it. Putting a DR 70cc kit on and going to change the carb to mikuni vm 20 with the weak-ends nc50 air intake. I'm curious if you have to eliminate the original oil pump and premix if you are going to use a new carb?

Thanks much for help/sorry in advance if there is irrelevant or missing info...