Years 2004-2006 is hit or miss, usually miss, with the RMZ and KXF (they were basically the same bike, just different color). The earlier models had overheating problems which has probably been corrected on this bike due to the Pro Circuit water pump. I think they may have had other problems as well though.
As for the 2005 CRF250r, it was rebuilt with titanium valves which could potentially cause for many valve adjustments. Stainless steel is what you want to replace them with to make them reliable.
It's usually a good idea to buy 2007 and up when it comes to 4 stroke 250's. But many times it's hit or miss, how you maintain them, and how you ride them. Someone could have put many hours on their early 4 stroke bike with no problems, while the next guy with the same bike could be on their 2nd rebuild. That's what scares many people away from 4 strokes. The later model 4 strokes are a lot more reliable if they have been taken care of.
If you dont mind a 2 stroke 250 bike, they have been nearly perfected for many years. And they are cheaper.
