Anyone else crack a cylinder wall in a wr 450? 05 less than 600 miles. Unbelievable. Put it away for a couple weeks after riding a tight Michigan single track with my son and pull it out to not starting with 50psi of compression due to a cracked cylinder. Mechanic attributes this to not going fast enough to keep air going through radiator. I know I am not the fastest rider in the world especially with the little one riding on me but we are not sloutches either. Regardless this should not of happened and am not happy. Some $500-600 later my get my bike back before snowfall. Just wondering if anyone else has had this issue and is there an aftermarket cooling fan you can get. Signed 'Boiled over in Mich'