Well, this fall I might want to sell my beloved 2010 yz125, and my 2004 FZ1. I for fuel injection. I am more comfortable with 4 strokes because I am used to working on cars. I want to get a 2013 kx250f, crf250r, or rmz250. I would keep it stock, maybe put a slip-on on it. If I changed the oil every three rides, and made sure my valves were within specification, how many hours do you think I could get out of the piston?