I've composed several 4 or 8 bar 'ideas' on my QY-70...but would like for them to loop continuously... Is there a function to "loop measures so-and-so"...? If I hold down shift + play...it attempts to loop what I have--but is adding a blank measure to the end of what I have before starting the first measure again...but when I try to delete that measure--it says "no data." Ideas?

Why not create a pattern using your 4-8 bar idea. This is exactly what patterns are for, and they will loop continuously as desired. Be sure to set the pattern length when creating it, and be aware that once you set the length and start to store note info in the pattern, the pattern length can't be changed.

There's a simple way, described in the manual to transfer information stored in a song into a pattern.

Good luck!