first off ... either that's not an F or it's an F with a lot of K parts on it
and to try and answer your question, if it's a knocking noise your concerned about , it's most likely the tappets need adjusting , but could also be the cam chain tensioner needs adjusting or god forbid the primary chain needs to be replaced
with the bike running , put your hand on the tappet covers (all of them) you should feel the vibrations of the motor , if you feel a tapping , adjust your tappets ....hope that helps