Re: what did you do to your motor bike today?
Get 2 similar $5 backpacks, and thread the straps through the other's buckles, you get a cheap pannier set. You can fix them in place by wrapping the supports with a strap from each side, or using zip ties, wire ties, strips of rubber innertube, even carabiners. Wongmart sells web-straps with quick buckles for $2 in the camping section, I'm always finding uses for them, from guitar straps, spare belt, shotgun strap, securing bike cargo.
1" roller Dax Friction Drive and Tanaka 3300 with mods.