How bad is it damaged? I've had some pretty badly damaged radiators before, one even leaking at the corner seams, but I had it repaired. Many places can fix radiators for about $45, and after being mig-welded they are stronger than they were before. This is why I stress the importance of radiator braces, whether you ride MX or off-road, it's a cheap investment that will save you from a DNF or a hassel of repairing/replacing.