they are slow. really slow unless you dump some cash into them...yamaha 4strokes are the most reliable ones out there...itll will be heavier and slower than a yz smoker but they are good trailbikes, especially for a beginner. a regular yz250f would be a better choice if you want to stick with the fourstroke
thats is true off the wr250 r that is the road based one . the wr250f is the same frame and suspension well not exactly the same but similarBelieve you can change the timing to match the curve of the YZ. I believe nick pointed out last year that the frame and suspension is different.