I made mine as well. I ordered the material from http://www.Strapworks.com The origional straps in my bags are about 3/8″ wide, they no longer carry the 3/8″ material so I used 1/2″ wide elastic strap. In my case there are a total of eight straps, two in each bag and two in each lid. I ordered 12′ of the 1/2″ wide material, I should have ordered another 4 or 5 feet.
At the same time I also ordered material to repalce the elastic straps on my tank bag.