???'s about engine break-in

[kmrcstintn]

I recently purchased a used GZ250 w/ 985 miles; the dealer did a courtesy service/oil change at delivery; I used their oil change as a 'flush' and did one @ 1325 miles; I have a weird observation concerning break-in...it 'feels' as though the engine 'loosened' and I sense better acceleration, slightly smoother shifting, and hopefully better top end, but riding locally I haven't had it over 50 mph (indicated) since I did the oil change;

now my ???'s...do these GZ's get better with age? how much more improvement can I expect? or is it more likely that I am getting used to the bike? thanks...