Clearance in mains- and prop-shaft damper are a) pretty rare (unless the bike was heavily abused, wheelies and such...) and b) normally only audible (a discreet "bang", like hitting metal with a hammer).
Dunno how "hefty" your take-offs are though...
When I really want to smoke it, I get a "uuieet" combined with a rubber-band feeling (hub dampers compressing) from the tranny line, but nothing on regular quick take-offs...
Proper condition of drive-splines and correct clearances between pinion- and ring-gear are confirmed?
On my prev '92 the "special washer" (warped spring-spacer) failing/braking apart... fragments caught infrequently in the tooting and the now very increased clearance on the ring gear caused quite an odd feeling at take-offs and load changes... got fixed under warranty the very next day (all bearings, shims, seals as well as pinion- & ring-gear replaced, clearances perfectly adjusted... the beST final drive I ever had, literally no noise, whilst the unit on the '00 ST always starts to chant when coasting...)