Could some give me the lowdown on 2001 jetting? It is my understanding my stock jetting is 500's I want to fatten my jetting by one size. I have also been told when you go above 500 the sizing changes, you have to go to 510N as a 520 is actually smaller than a 500.

Could someone help me here as I have added a dynoport pipe, VF-III reeds and I want to put two TPI valves in and I am told I need to go at least one main size larger and put a shim under the needle to fatten the mid range.