This is not my bike, it happened to a friend of mine at the track today. 2010 YZ450F. Racing Supermoto. He said he was coming onto the main straightaway, and shifted up into 3rd gear and heard/felt a bad crunching noise. In the next corner he downshifted into 3rd expecting to use some engine braking, but the motor completely freewheeled, as if it was in neutral. He pulled off the track. Now the bike runs and shifts normally, except 3rd gear doesn't engage at all. Does anyone know what may have broken in the transmission? Is this a common problem on this bike? Thanks for any info.