I have been riding now for about two years i have a yz125 right now but i am looking for a new bike. Since i do mostly trail riding i would like a four stroke, but i have heard that when the blow up it cost around 1500 to get them fixed. I was just wondering whats the chances of me dealing with that. I want to spend under 3500 for a used 450. Also what is some other things that i would need to repair on a four stroke thats not on a 2 stroke like valves. Would a drz 400 be more reliable then a mx 450 and is a 450 more reliable than a 250f thanks