Here’s a tech tip for your Harley top-end rebuild. Before you can install your pistons you will need to check the ring end gap. Push the ring in cylinder, use the piston to push it down in a little bit and measure your gap. Your manufacturer’s spec is check with a feeler gauge.
If it is tight you will need to open up the ring end gap. No need for a fancy (expensive) tool. Put a file in the vise and on one side of the ring file it down nice and flat. Check as you go.