Hey ben, welcome mate
The 600 is all about high revs so if it is flat then could well be restricted
A few members have or have had theirs restricted so should be able to help you out.
Hope you enjoy the bike, does it run well apart from that?...if it doesnt then maybe something else is at fault.
Something else to check when you get time, whip the front sprocket cover off & check the sprocket nut, theres a known flaw, go to the search bar in here & type front sprocket nut & you can read all about it.