A few days ago I've asked the German site (both the CB500 and CB550 sections) what experience they have with various sealed chains (both O-ring and X- ). I will also ask the French and Italian site. I hope to report more on this in the foreseeable future. Sofar a German CB500 owner claims he has good results with a DID-VX.
I quote him in translation:
... My old chain had a 25mm width which had milled a bit of the casing. The DID-ZVMX has 24,9mm width and would also rub...
Another CB500 owner had reported he has good results with this ZVMX type [explanation Deltarider]
... That's why I went for the DID-VX which has a width of only 23,3mm and this chain runs just free. One can even get a 2/10 feeler gauge in between, when chain is fully pushed towards the casing.
I'd like to add the following remarks.
There could be a difference in clearances between the CB500 and CB550 models and even between the various CB550 models, K and F.
Both the CB500 and CB550 models can develop considerable play at the rear wheel sprocket carrier which may have an effect on the drivechain's trajectory. Please report your findings, positive and negative.