new air filter set up

[Jvacustoms]

I have installed a 4 inch k&n style conical universal air filter with a pvc adapter straight off the carburetor. and I am unsure of where to adjust the carburetor to make the bike run right. It takes of smooth until you hit 1/4-3/4 throttle which I think is needle jet settings but I am not sure if i need a new needle jet or just to set that one properly i have already moved the needle jet washer to under the eclip but that doesn't seem enough. can i just add another shim washer below the eclip or do i need to buy an jet kit so that I get the adjustable needle and some other jets to try. also i read that in "Jaime" gz250 power increase that there might be need for a larger than 130 main jet with the air filter and exhaust modifications. It does good in top and bottom throttle points but revs like hell in the middle.
I have tried just adjusting the mixture and that seems to be moot, until i get the needle fixed.