Thanks for the reply but I have one of those. My problem is that something seems to be out of balance on my RM-48. First, I took the blades off. Still wobbling. Then I took the belt off, same problem so I think the trouble is in the small amount of slop with the adapter. I had one of the correct yokes and gave it away for shipping costs. I bought this used mower a little over a year ago. Popped the belt yesterday and put a new one on. Same problem. Looks like I'll have to pony up the bucks and buy a new yoke. Sure hope that will fix it. I have new u-joints but haven't put them in yet. Old ones feel tight. I should add that my adapter is not identical to that one.