The best approach would be for Harley to update its obsolete design and replace it with a modern one. Since they haven't done it in the eight or more years the new garage door openers have been on the market, I'm guessing it isn't even on the priority list.
There are many ways to make the system work with the new Chamberlain and similar openers. The least expensive method involves running the wires from the Harley receiver to the smart wall control, NOT to the opener itself, and soldering the two wires to the pins in the wall control for the button switch to operate the door. Then you have the option of using a remote for your actual door, as detailed in this thread, either mounted to the bike with a remote pushbutton or just used like it would be used in a car. Then there are solutions that use the system on the high end openers that allow for wireless control from various locations. Lots of choices are out there. For those who have bikes that didn't come with a Harley system, I highly recommend you not buy one. There are much better options out there.
JMHO - Jerry