I recently picked up a Triumph Tiger tank bag off eBay. I love the bag (nice medium-size, but expandable to Huge. Lots of pockets, clear map pouch, a pocket that zips-off into a fanny pack, rain cover, etc.), but didn't like the attachment system.
The bag quickly attaches and disconnects from the base pad with nylon quick-release buckles, and several square inches of velcro keep the bag from shifting around on the base pad.
The foam and nylon base pad is secured with 1-inch nylon straps and buckles. It's not permanently-mounted, but it may as well be. You have to remove the seat to thread the straps into the frame, and it's also a pain in the keister to secure the front of the pad.
If it's that much of a pain to remove and re-install, I can see that I probably wouldn't remove it often to clean under it, and the paint on my tank would suffer for my laziness.
There has to be a better way.
Enter SW-Motech's gascap ring mounting system.
I like this system, but not their bags (very few have a see-through map pocket), so I decided to use the SW-Motech mounting system on my Tiger bag.
I made this base plate from .125 aluminum. The box on top is so that I can recess the mount, allowing the base plate to sit as low as possible.
Painted, with bag attachment hardware and velcro...
The finished product installed...
The SW-Motech parts are:
RAM base, part # TRT.00.475.225 $38.00
Triumph Gas Cap Ring, part #TRT.00.475.160 $25.00
Twisted Throttle Ltd
1080 Kingstown Road, Building 2
Peacedale, RI 02879
9:30 AM - 6:30 PM (Eastern Time), Monday - Friday
6:30 AM - 3:30 PM (Pacific Time), Monday - Friday
Cupholder, made from a scrap of one-inch aluminum and a plastic Jif peanut-butter jar.
I use a 20-ounce Coca-Cola bottle because they're more slim than others. I drilled a hole in a cap and made a non-disposable straw from a sixteen-inch length of plastic tubing. I bent the end into a 90-degree mouthpiece so I can slip it under the chin guard of my full-face helmet.
The insulator is a neoprene beer bottle sleeve. I have it attached to a retractable key ring. I once lost one of these on the road when a truck passed me and the wind gust blew the bottle out of the cupholder. So now I have a retractable lanyard.