honda sells a big bore kit for a 250ex its a 282cc called 300ex.j/k im sure there is one somewhere.

 

Say what? I don't get it?? If he only wants to bore a 250ex, I really doubt he's ready for the 400ex!

 

Can you guys give anymore usless anwsers. He didnt ask you if he should get a 300ex he asked for a BB on a 250ex. How do you know if he is ready for a 400ex or not? Anyways first does your friend have any mods at all on it already. If not he should start with a exhuast.. HMF, WB, FMF.. the list goes on.... Does powerroll really have a BB for a 250ex?

 

just go to rockymountainatvmc.com .... does your friend have a pipe airfilter and jet already??? if not that will give the bike a good amount of kick......my anyway rockymt.. has a wiesco piston that you can buy 20, or 40, many more?? over.... it comes with everything but top end gaskets.... i would recomend not to bore it out unless it NEEDS it.. but if not i would get some aftermarket parts, exesept what you have or sell it save more money and go with a early 2000 400ex

 

oh ya... haha the pisyon is 107$