Hey. i am in the middle of building a Lonestar 250R geometry No-link framed yzf hybrid. i got a yz400f motor with the frame and had a few questions. my first question is the motor worth using. should i just sell it and buy a 426 or 450? I dont want to go spending alot of money buying a different motor and then spending money on that motor too. so here is my next question. if the 400f motor has alot of potential how can i get that power out of the motor. i was thinking of doing the 417, porting the head, and gettting some new oem ti valves. I am pretty new to the 4-stroke scene. i could tell you how to get the most out of a 250r motor but have no idea when it comes to thumpers. any help would be appreciated.