We bought a 2007 CRF150RB about a month ago. All seemed ok, Sunday at the track it was a bitch to get started, finally go it to run. 15 minutes on the track it seized. I changed the oil, oil filter and air filter 2 days before. At first I though it must be something I did. Now I don’t think so, I pulled the motor and checked oils, Clutch and motor and both were okay. I thought I might have put the oil filter cap on wrong, turns out its dummy proof. I am no “wrench” so the motor is at someone who is, but I pulled the valve cover and saw a chuck of metal was there from where a valve smashed into the “Cylinder Head Cam holder”. There is only about 20 hours on the bike. Just seems weird this would happen. I called Honda to see if maybe I could play the CAM recall card, turns out the bike had a new CAM install Nov 2008, but I am also on the Swing Arm recall, dropping it off tomorrow while we are getting the motor rebuilt. I am not ruling out something I did, I am not sure off all the damage yet, my “guy” is the “Wrench” for Jake Canada and they are racing Hangtown so I am not top priority. Any way any thoughts? If the whole top end is trashed, should go with a 170cc? Could be something I did? Maybe a water pump? Is that common? Where is a good deal on top end parts? My kid (13 yrs old 90 pounds) got bored after his bike blew up and rode my 2011 CRF 450r on the track! Kinda funny looked like a jockey riding a horse! thx!