Switched to synthetic oil and trans shifts sooo much smoother.Notchy shifting is all but gone.I've got 2600 miles on my ZZR and put Honda full synthetic oil in it this morning.
I'm sold on this stuff even at $9.50 a quart.

 

I've been running full syn since 5400 miles. I now have 66k. Shifts sooo smooooth. It will get a little notchy and harder to shift the closer it get to 3000 miles. That's how I know it's time for a change.

 

The "top end" of the engine will look like new if you keep using syn, too. You'll be amazedwhen you do a shim job or other minor surgery.