Mine was a very snug fit. I torched it briefly with a propane torch - heating evenly and gently now (didn't get it above around 180F-200F), and then allowed the crank bolt and washer to press it on. Fit just fine I think. If you like hone it a bit for a better fit, sounds like a good idea.

My performance products Euro dampener was as you mentioned, had to be opened a bit to fit.

Ron