Hi Martin, yes those four 'Metalastic' bushes in the CB250RS rear hub are utter bar-stewards to swap so much so that I never even tried. As they've now been in situ for 40 years there has to be some steel to alloy reaction. I found that as long as the items are still in a recognisable state with the rubber parts intact, a lot of 'slop' between the sprocket and the hub can be successfully reduced by the fitting of a thicker washer under that large circlip. Some years ago my 250 was an MOT failure (by a worthy on the Stourport to Worcester Road who later was told by Ben at Alec Dorrell's "All they're all like that don't worry about it", but it was too late then as he'd already failed it. I scrounged a piece of 2mm (I think) steel plate off a friend and using the original washer as a template I made one, took the bike back later in the day and it passed. All the best.....Dave.
That's jogged a vague memory of waggly sprockets on zsuperdreams in the 90s, and I think thicker washers were the trick there. I was told that the sprocket eventually wore the wheel out, as it was harder (never found out, my 250N died after 3-4 years of urban commute, outside parking, vandalism, and trips to Shetland, Norway, and Cornwall from Embra).
Never an issue on the 250RSs I had, but only had one RSA (Deluxe). I'm sad to say i blew that one up and to my shame it was my fault. Lnly time I've ever done that.
Xbally, delighted you got a cheap easy fix! Looks like God not on his Harkey...this week.