FYI- Backpacks suck and can be dangerous! If you have something in there weighing 5lbs or more, and the pack isnt totally full, nor strapped to your back as tight as you can get it, when you go around corners the weight will move around, can throw you off balance, and can even cause you to lose control and wreck your bike!! Trust me, I've almost done it myself and I'm an excellent rider. Been riding over 30 years.

You need to invest in a quality STRAP ON tank bag. [ The magnetic bags work good in theory but are also crap IMO ]

There's probably a good one strap on bag available from Suzuki or possibly even FOX (thats the brand I have). You have to remove your tank to install the straps, but then once the straps are on it works great. The bag attaches to the straps with quick-release buckes and can easily be removed. The good thing is, it holds more stuff than your backpack can, keeps the weight centered over your bike so you never have to worry about being thrown off balance, and even gives you a nice semi-comfortable cushion to lay on when your back starts aching from those long distance freeway rides.

Mine also has an expandable zipper on it. So when it's zipped "small" it will probably hold 12 cans of pop with room to spare. But if you have lots of stuff to carry like food, clothes, or an extra helmet, you unzip the zipper and it doubles in size by getting twice as tall.

Oh yeah, it also has a large clear window on the very top so you can put a map in there to help with directions, and the bag is mostly waterproof!

My FOX bag was $80 about 10yrs ago when I got it and it still works great. I have a metallic purple Honda CBR600 and it's a blast to drive. Nothing like doing 150mph+ down the freeway and still getting 50mpg LOL.