OK, '03 525 exc -greatest bike ever! better than my '72 Bultaco Matador!! it was overheating and steamin' - you know what i'm talkin about, and then went BWAAAAAAAAaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaah and then silence - it had to have sucked a valve. OK, so how do I get the head off? I can't get the cam chain off the gear to slip the cam out and pull the head. I have: taken the tensioner off backed out the gear bolts but couldn't spin the gear to pull it off tried pulling the gear side bearing off the shaft no luck. help. What's the trick?