As as guess, about 56 mph.
Before the sprocket change, my speedo was spot on and the average top speed at sea level, llevel ground, no tuck was 52.
The motor could do 52 in 4th gear and 5th gear and 5th gear did not seem to get to the power peak.
With the sprocket change the speedo reads 2 mph faster, it may be 1.5 or 2.4 mph faster, more testing needs to be done.
But I can hit 58 to 60 mph which is about 56 to 58 mph roughly.
I found myself doing 62 mph indicated behind traffic!
That is a NICE boost for just a sprocket change.
If I pulled the snorkle off that would be even higher!