I am tryikng to get a rolling chassis of a CRF 150R Expert. I dont know what type of motor to put on it to get the best performance plus reliabilty. I dont want to be working on it all the time, but i want to keep it light so it will be a good enduro bike. Im 16 and only 145 pounds so im thinking a 250 motor. But should it be a CRF, WR, XR, or something else?