Thought I would share my oppinions of the Saddlemen #3516-0109 universal rear seat bag and how it worked on my R3R. It cost me 100$ delivered to my door and included everything I needed.
The bag secures to a mounting pad that secures to you rear pillion with two supplied straps the tighten to the seat by double rings just like are used on helmet straps. They are easy to slide under the rear seat above the fender and I didn't even need to unbolt the rear pillion bracket to do so. In the pictures I have the main seat removed but that was not necessary to facilitate the install.
The bag secures to the pad with both Velcro on the underside of the bag and three straps that tighten up via knuckle clamps installed into the bag. Two front and One in the back. It has a lot of movement but seems quite secure.
Just for the test I loaded it up with all my cold weather basics. Chaps, Rain suit, Winter Gloves, Thermal liner, and a spare helmet visor. There is plenty of room in the bag and it seems to grow as needed the more you shove into it.
It is well thought out with a pocket in front that has a rain cover you can deploy should you get caught in a gully washer. It has additional side pockets for use as well as 7 rings around the perimeter on top and 6 around the bottom sides for attaching bungie nets or bungie cords to it
It stays put. I left it on, loaded up, and took it for a short 60 mile jaunt through the hills and when I got back It was the same place it was when I left.
It seems built to last. Good product built with sturdy materials.
The only two bummers I see with it is that you have to sacrifice your back seat for it but in an emergency should you need room for a passenger it removes in seconds. Secondly, when you mount and dismount the bike you have to kick your leg quite high to swing it over the bike.
But those two things seem to be a small price to pay for a quick detach long haul luggage option. that costs only 100$ us delivered to your door.