I built this for my Super Tenere, but it's adaptable to pretty much any bike; you just need a hardware store U-bolt big enough to fit around whatever bar you're attaching the mount to. It's a simple open ended box, made from 1/8" ABS sheet plastic. It's measured to fit a specific phone, in this case a Droid Turbo. All the aluminum pieces were made from hardware store aluminum stock, and the U-bolts came from there too. The RAM style ball mounts are just 1/2" aluminum tubing, a 1/4-20 machine screw, and a threaded polypropylene ball from Mcmaster-Carr (about a buck apiece).
The sunshade flips forward to insert and remove the phone. The phone is held in place with a simple aluminum piece bent at a 90 degree angle. The camera on the phone is actually able to take forward looking photos or video while it's still in the mount.
I had it on the bike for a recent trip up to Cape May, NJ, and it's solid. Mainly I needed it because, when I have a tank bag on the bike, my current cell phone mount is unusable. The sunshade works pretty well, and the phone is visible in bright daylight.
There are more photos here of the construction: https://www.stromtrooper.com/members/...-sunshade.html
Feel free to adapt the design for your own use.