I'm new to the forums. I'm sure this queston has been asked before. I have a stock 1991 FXRS and would like to put a 150 Dunlop on. Is there enough room inside the fender ? What mods have to be made, if any, to put it on.
I have a 1985 FXR with a 150 Avon Super Venom. I had to space out the pulley on the wheel with a 3/8" spacer. My pulley came with a chrome cover that had to be removed, because the pulley is too close to the swingarm and rubbed with the cover. The axle also needed an extra bushing/washer or two between the swingarm and the pulley to help keep the swingarm from clamping in on the pulley. The belt rubs the tire a little bit when pushing the bike backwards, but doesn't rub when going forward. It is a very tight fit, but definitely doable. As for fitting under the fender, I haven't had any problems with rubbing. I'm running stock height, so I'm not sure if rubbing would be an issue on lowered bikes.
At one time I came across a compiled list of all the various and in what direction H-D wheel offsets are. Some years and models had very large (at least 3/8") offsets. Anyway, if memory serves me right the FXR had a wheel offset to the left. So in theory anyway and if this is actual fact, centering the FXR wheel should free up some space for a wider tire and more belt clearance. This may or my not require a custom pulley spacer. Sometimes depending on the spacer thickness, some of the wheel flange needs to be machined off so the spacer can be made with a locating flange for the pulley. I've never been keen about those flat faced pulley spacers that don't positively locate the pulley center hole.