So after hours of searching over the FAQ and various threads on this site I have resorted to making a new thread. This is my first post on TT but I am quite familiar with forums as a whole so here it goes: I recently bought a YZ400f with a 426 top end on it and I took it out to the desert and went on a group ride with some more experienced riders than myself. Needless to say the took me on one hell of a ride and I dumped my bike twice. The first time was a soft landing and the second time was a little harder but iI was uninjured in both. the problem is that on the second drop one of the lower coolant hoses came loose and started a slow leak. once I started riding again, the pressure built up and dumped all of my coolant out without me knowing. the bike kept running for a while, then i stalled it (let the clutch out too fast) it became harder and harder to start each time i shut it down (using the killswitch). we ended up bump starting it to get it back to camp (10 miles) then I put it on the trailer and went home. The next day I tried to start it and nothing. I still have what feels like a lot of compression (the TDC lump is still hard to push through without using the decomp lever) so I changed the spark plug thinking that I fouled it when it was on its side but that diddnt fix the issue, so next I dropped it off at a local shop in Vista, CA to have the carb cleaned and re jetted since the previous owner had it set for 3000- 6000ft above sea level and I live at sea level. So the shop cleaned the carb and rejetted it but they said it still wont start. I told the tech that it had overheated bad and he said that the piston rings were probably fried and it would be $600 to redo the top end. What do you guys think? is that a reasonable assumption and if so is that a reasonable price? I'm new to riding so I'm struggling a little. Any help would be appreciated. Thanks!!