Enduristan tank bags.
First piece of gear that goes on my bikes every time.
Have just returned from NZ, 10 weeks, almost 15,000 kms on my R80gs, in all types of weather and roads from motorway to single track. It stays on the bike down there. In the last 2 years I have carried/used that bag for almost 120,000 kms through Europe, Asia, Oz and NZ. Still works great. It is just like a womens handbag, it carries everything that you will need for a tour, weather its one week or one year.
In my case it carried my pc, all chargers needed for the pc, mob, camera's, LED light, med's, toiletries, dunny papper etc, spare glasses, stubbie holder with a Swiss Army knife,and a Leatherman, hat, tools, inc small multimeter, tyre gauge, cable ties plus lots more that I can't remember. The map storage is held by velcro to the main bag, and takes A4 sheets, in my case I had a m/c magazine, NZ atlas, and probably a dozen NZ AA folded maps of each Island, stowed there.
Only draw back the map holder is not waterproof, so put everything in snaplock bags, too easy.
It is quickly detactable.
What more can I say.
That and your backpack are your best travelling companions, period.
Keep me searching for a heart of gold, and I'm getting old (Neil Young)
Still homeless, armless and legless,
And proud 7th Day Adventourist