What happens is shifting from D to R while moving disengages the gearbox until the vehicle slows down to a crawl (less than five mph) before connecting the reverse gear, precisely the reason why ...

On a 2020 K 1600, a convenient button on the left handlebar controls reverse, eliminating the manual steps that many R 18 owners have illustrated. To shift the bike back to neutral after reversing ...

So, to engage the reverse function on your Harley-Davidson trike, follow these steps. With the trike turned on, shift into neutral gear. Release the brake and disengage any other braking functions.