300cc powervalve, wanna go bigger 330cc?

[georgedoggy]

hey guys,

i run mx with my 250r, it has a duncan 300cc cylinder and goes hard. my problem is im 250 pounds and i need more power to gain the advantage over those damned 450's. im not getting beat, but its hard when they are only 160 pound riders. im losing weight but i need more power. how much more will i get with a 330 kit? is it a matter of replacing the sleeve with a duncan 340 sleeve? i can also get my hands on a 4mm stroker crank? maybe i could the current sleeve and run the stroker?
anyhelp is appreciated.

[Blown 331]

I don't have the answer for ya but if you go with a 330 I would be interested in your old set up. I'm trying to get my 85 ATC250R to beat my 450R and that would do it, I'm pretty close with the stock cylinder.