I am looking into boring my 400ex to a 426. I was wondering, do i need to re-sleeve it, or when i get it bored, are they more or less boring the sleeve?? This may sound stupid, but i have never done this before. Thanks for your reply in advance...

 

i recommend the 440 sleeve, so your not wasting your time.buy it all in one kit. plus you have more room for larger pistons in the future, if you ever have to hone it out again. ie: new rings