Premix is a better idea for oil with a bbk. Otherwise you are getting a lesser mix of oil (more air per rpm, more fuel, same oil flow.
I believe it is the same on most similar bikes. On the super 9 i did it looked just like a gy6. I did it like so
Disconnect oil line from pump inlet and drain.
Remove hose between pump outlet and intake manifold.
Remove throttle cable connection from pump (wrench to loosen the nut)
Remove the single bolt holding the pump in.
Pull out the pump housing. Slide off internal shaft. This will not go back in.
Reinstall pump housing. You can either cap the nipples with vacuum caps or what I did was I cut the hoses short, and found bolts/screws to slide over one end, and zip tied to seal off the ports.
Similarly seal the port on the intake manifold and you are good to go.
It is probably overkill sealing the pump inlet and outlet, but I think that without the shaft, you dont have a full seal so better safe than sorry. The intake manifold nipple will need to be sealed, however.
Boom, job done. Took me like 10 mins. I recommend removing your seat to get to it
