my 400ex

[dirtyredneck]

i have a 2000 400ex with a 440 bigbore kit, stage 2 hot cams, i am rebuilding my head and want to go 1mm bigger on my intake and exahust valves. is it worth the money?

[crom A zone]

not enless u got full system pipe  no air box and a bigger carb

[hellrazr]

I would assume since you have a 440kit, with a different cam then you porbably have a good exhaust.  Do you have your head ported?  That will be alot more beneficial then larger valves?  If you are ported then the +1 would probably help some more since you are running a larger bore already.