my new 400ex

[400exboyz]

i just got a 2003 400ex about a week ago. it has 155 main and a 40 pilot jet and i just put a pro circut t-4 on it. i havent got to ride it with the pipe but it seems to run good. im wondering if this is a good jet for that pipe? i am also thinkin about taking the choke out and grinding down the welds in the header. would i have to rejet for this? if so what jets? any other good mods?

[2005honda400ex]

i have the 440 wiseco big bore kit in mine and it makes a huge difference in power i would reccomend putting that kit in it