Those old revolutionary guards one's blasting (5)
I believe the answer is:
Here is my best explanation:
'blasting' is the definition.
'those old revolutionary guards one's' is the subsidiary indication.
'those old' becomes 'yon' (archaic pronoun equivalent to 'those').
'revolutionary' says the letters should be written in reverse.
'guards' is an insertion indicator.
'one's' becomes 'is' ('I' can be a synonym of 'one').
'yon' written backwards gives 'noy'.
'noy' enclosing 'is' is 'noisy'.
(Other definitions for noisy that I've seen before include "Vocal", "Very loud", "like thirteen [HARD ROCK]", "very vocal", "row", "Full of disturbing sounds", "Clamorous", "Raucous", "Unpleasantly loud" and "Loud, rackety".)