i have a question on a 2004 400ex i bought a wiseco big bore kit for it and ive heard many storys on how to put it in some say i have to get the sleeve bored out and the new one pressed in and some say i dont have to do that that i can knock the old sleeve out and press the new one in myself who knows for sure

 

pay to have it sleeved correctly and install heavy duty studs or ull be changin headgaskets every ride

 

it depends on what size of big bore kit you got

 

its a 440 big bore kit