As per an old post of mine, I'm using Kuryakyn drink holders, front and rear. The handlebar front one is for a 1.25" handlebar, so I used a 3/4 " wide piece of thin PVC pipe as a shim and it tightened up perfectly.
The rear holder is a Kuryakyn #1785 - I don't see it listed anywhere anymore, and I think I bought it off of Amazon, but it works fine for the wife.
I hope you can find something similar.
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