Rear shock linkage knock

[PieEater]

I would ask your tester to confirm if the knock was felt moving the swingarm up and down or side to side. Some up and down knock is standard on Gen1 Fazers and is only felt when the bike is on the centre stand and there is some play at the rear wheel when lifting it up, when the bike is on the road any slack is taken up and it honestly is a non issue. If the knock was side to side then yes it would be worthwhile looking at the bushes and bearings but I somehow doubt this would be the case. Entirely up to you how you pursue this, when I first took my bike to be MOT'd the tester gave me an advisory for the same issue but after explaining to him that the Fazer has a fairly long swingarm and that some free up and down play at the rear wheel when no load was on the bike was usual he has never given me a further advisory in the 11 years since. if you do look at stripping the linkage for inspection or to replace parts some have reported torqueing the bolts back up with the bike on the side stand reduces the inherent free play but I don't think you will ever eliminate it.