When the MoCo went to the rubber mount chassis in 2004 the rear of the bike was widened to accommodate the 150mm rear tire. The sissy bars and pads were the same for all 883 & 1200’s. You can choose from H.D. Products or many after market suppliers.
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Keep smiling cause it makes everyone nervous!
Everything happens for a reason. Sometimes the reason is that you’re stupid and you make bad decisions.....
I recommend trying Viking Bag's sissybar backrest. I've been using one of their sissybar on my Sportster, which I purchased a few months ago, and I'm really pleased with its quality and reliability. Based on my experience with both the company and their sissybar, I confidently recommend them.
My bike came with the detachable version and I like that since I rarely ride two up. FWIW I also made a rack to bolt up to the detachable HD sideplates and that is very handy...