The rear gs1000 spoked wheel needs new bearings to go in. The standard gs1000 has a 20mm axle. My Gs550 has a 17mm axle.
I thought about converting to the 20mm axel (I've got the 20mm axle, spacers and rear caliper bracket that all came with the set of wheels i bought locally for £15 - I was told they were gs550 wheel but I realise today they must be gs750 or 1000 because of the axel size. I just wanted the drilled discs) but the 20mm axle is quite a bit longer than my gs550 17mm axle. So I guess whatever bike the wheels came from (650, 750, 1000?) also has a wider swingarm.
So to cut a long story, long

... I'm getting 17mm bearings to put in.