Sometimes even when the bearings are properly installed/spaced, the ears may still be a little off. The rubber spacer ring that sits atop both ears can be shimmed upward, filling the gap you speak of. Add a rubber o ring (or two) UNDER the factory spacer ring to slightly raise it. Only the rubber spacer will show, the o rings will be hidden below. I know that this works on the 550, you may give it a try for the 750 tho. Just a thought.