i have lower right side noise similar to a loud cam chain. checked out roostns' post about similar noise and decided to check it out per hicks routine. after removing the side cover, found no apparent play in the cb drive gear. bike is a '99 yz400 with about 500-700 miles. before the noise got louder, the (3) previous rides were very tight eastern woods. rode very fast with a lot of clutch. the clutch also seemed to get harder to disengage as the day went. each time we stopped, the clutch was easy again for about 20 minutes, then it got very hard again. since we rode for about 2 hours before the clutch got harder, and it was cold out, it could be that my fingers got tired. the unusual thing though, was if my fingers were tired they would normally be sore for a few days later. not this time. what could possibly make the clutch harder to disengage? also what could still be causing the cam chain type noise? or is it just due to milelage? any thoughts appreciated.