Send your top end to Ken Oconner racing, He will hook your sh*t up and yes you will take any of those hills in treverton, and smoke the 125 in the process! If your local engine builder doesn't know how much the cylinder can be bored I'd stay away from them, you'll end up with a piece of sh*t. I'm speaking from experience here, Ken found so many little issues with quite a few motors that could of caused disaster in few short rides he relly knows what's up, tell him what kind of riding you do and what kind of porting you would like, he will take over from there. My son's bike is fast as hell and it's not even jetted properly yet!