How much power from a yz426?

[A A R O N]

Can anybody give me an estimate on what kind of horsepower a yz426 dirtbike motor makes if it's on standard bore with an aftermarket piston (not high compression). How much power can you get out of it without boring it over? Like, maybe a cam and some mild port work. I just need a quick referance if anybody knows.
Thanks

[86350x]

44hp stock at the rear wheel. with those mods, I'd say maybe 50. It will run with all the new 450's the way it is. Don't let the fantasy camp tell you any different. They are so close its all rider. My lightly modified wr426 and mikes cr450f are almost exactly the same. Mine just runs away from it on the topend because of the enduro gear ratio's.

Not much of an improvement to be had over the stock cam, or piston for that matter. Head porting will net you some hp. A full expensive exhaust will get you more hp, like a wide open race pipe from white brothers, or akropovic. But the stock exhaust is really hard to beat too. I'd save my money for other things for your bike.