I have an 07 EXC 450 and just ruined my second hub due to sprocket bolts coming loose. After replacing the first hub I put on new sprockets and chain with new bolts. After every ride I would find one or two loose then tighten all to the proper torque spec then even tighter when they would loosen. Then I put new bolts again with red lock tite and they still came loose. After checking the countersink angle the bolt and the chamfer on the sprocket match at 90 degrees. The chain is kept within the manufacturer's suggested slack as well. Are there any remedies? Should I try an aftermarket hub?