Been a member for a while but didnt post anything until now. I purchased by 2010 YZ450F about 6 months ago from a racer. I checked everything out on the bike and it seemed great. He said he just upgrades bikes every year and this was his previous year bike. I have been trail riding and riding mx and supercross at a local track. It does have suspension work by Total Control Suspension for a 220# rider and I'm 190. Long story short, we were riding at the track yesterday for a few hours and when I parked to talk to a few buddies one of them noticed that the frame was cracked close to the steering head. After further investigating we found that it was craked on both top tubes that connect to the steering head about 3/4 of the way around. The tube that comes down from those tubes and connects to the down tube is broken completely off the down tube. The down tube is cracked about 1/2 the way around. So it seems that it would have only taked a few more landings before it completely broke the steering head off. ALL of these cracks started or are completely through the center of the welds. All of the cracks/breaks look clean inside, like a fresh break. Is this a common problem on these bikes? I called Yamaha hoping for some help but you all know what they said, its not a defect. Is there anyone else that I can contact? I talked to a yamaha customer specialist, but had hoped to talk to an engineer. I can include pics if anyone would like to see them.