The elastic belts in my Givi Monokey V46.N top case are old and the elasticity is gone.
You can buy replacements from Givi for about $35 shipped, but given all that needs replacement is the elastic itself, that seems wasteful. Here's a way to replace just the elastic.
- Remove your existing elastic and anchor points. This video gives a great illustration of how to remove the waterproof rubber gasket and unscrew the retention screws for the anchros : https://www.youtube.com/watch?v=YWHHd3nmm_g
- Buy some 25mm wide elastic. I found lots of vendors on aliexpress.com selling them shipped for $4 or $5 for 4 meters. I used search terms like "25mm" "elastic bands". The one I bought (though it may be gone at the time you're reading this) is https://www.aliexpress.us/item/3256802906335899.html tited "4~8Meter 20mm/25mm/30mm/35mm/40mm/45mm/50mm White Black Nylon Highest Elastic Bands Garment Trousers Sewing Accessories"
- Look at your existing elastic to see how the elastic is folded over and sewn to connect to the anchor points. Also pay attention to the orientation of the anchor points and the center clips so that when you replace the elastic you can assemble it in the same way.
- Take some measurements of your Givi top case to know what length of elastic you want each one to be. Measuring your existing elastic won't help because it's all saggy and much longer than it should be. For my V46 top case, I measured 17 inches from one anchor point to the other. Given that you'll want to both fold over the end of the elastic and loop it around the anchor points, you'll need to add about 2 inches onto each end so 21 inches total should work. 17 inches from anchor to anchor for both bands will put them under elastic tension whiched seemed ideal. 18 inches on each and they'll just be slack which probably isn't what you want.
- Cut your 21" inch lengths of elastic band, cut the center clips and anchors off the old bands, using a sewing machine, sew the elastic on each end to connect it to the anchor points. Don't forget to put the center clip on the band before sewing the anchors on.
Here are some photos of the old elastic and the orientation of the anchors and center clips

