Doing wnat training wheeler said will remove all tension from the cam chain. Do not loosen that small bolt. I believe that is for assembly of the motor, so you can remove tension by removing the small bolt, inserting a punch push down and tighten the larger bolt to hold that slackened position. From what I can tell here either your cam chain, the tensioner, or the guide is is worn... maybe all of them. I had that same loudining happen to me with a fairly new cam chain....It was worn out after about 1.5 years. New chain....no noise.
Sam from Florida
1985 BIGRED $ 200X