ElectricMotorcycleForum.com

I have a very occasional use of saddle bags and I wanted a cheap and simple solution to add some carrying volume.
You can search on internet for "SA-212 Komine Saddle Bag", and you will find this pair of bags for less than 40€.
If they are not sold with the bags, you should add a pair of plastic sheets that can be put at the bottom of the bags and make them more rigid (but I did not put them in place in the pictures thereafter).
A zip can extend each bag to a volume of 29 liters.
To mount the bags for the first time, since the documentation is in Chinese only, I used some youtube videos in order to understand how the straps should be positioned.
Once understood, it should take less than 10 minutes to put in place, and about 2 minutes to dismount.
You will not be able to have a passenger with these bags in place.
To save passenger seat, it would perhaps be possible to make a mount similar to that depicted in http://electricmotorcycleforum.com/boards/index.php?topic=7188
Here are 4 pictures, and you will find more pictures with better definition here.