I have an 86 fxrs-sp and I bought a set of Hooker stepped drag pipes off of ebay.
The post said they were for an 86. when I got them the instructions said it was for an 86 and a 1/2. "hmmmm what the hell?"

went through my mind.
Apparently the rear break setup sets above the frame rail on an 86 and halfway through the year they decided to move it below the frame rail.
So now the bracket to mount the pipes wouldn't fit against the tranny.
I had to make two spacers on a lathe to bring it out but that made the pipes a little crooked.
So my next step is to fabricate a new bracket. It shouldn't be to hard.