Find yourself a good used KTM 300EXC. Plenty of power, these things are like mountain goats, light weight, way less expensive to rebuild than a four stroke (and if you are looking at a 2 to 4 year old four stroke, it will need a rebuild) and, they hold their value way better. I am 6-4 and 280 and I ride a CR500, the 300 EXC pulls my old fat ass anywhere I want to go.