1984 Official Honda TRX200 Shop Manual, Page 61Get this manual
CYLINDER HEADVALVES INDEX MARK
Remove the timing mark hole capTurn the crankshaft with the recoil starter unti the cam sprocket "0" mark and cylinder head index mark alignRemove the cam sprocket bolts and cam sprocket
HONDA TRX200
CAM SPROCKET CAM SHAFT CAM CHAIN
Remove the camshaft, Suspend the cam chain with piece of wire to prevent it from falling into the crankcase