OK, I was adjusting the valves, and one of lock 10mm nuts is really REALLY tight. So tight that I couldn't get it to turn with my little box end wrench, and I put the 3/8 drive socket on it, and I was starting to get worried I was torqueing on it so hard (that is when I stopped, and decided to ask the masses).
Particulars, 2003, 26k on the ODO, and 7K from the last valve adjust. Just to clarify if his helps, it is on an intake valve, and the clearance as it stands stuck is between 0.20mm and 0.25mm
Since it was a little loose, I decided that was better than breaking something by trying to loosen the nut.
Many moons ago I broke off an adjuster from over tightening (on a CB750k bike). Back in the day though the dealers had those parts in stock. Loosening, yeah the potential is there that the screw could snap off. I did have one that was tight on my Connie the last valve check, and I had to break it loose with a socket/ratchet combo, no problem, I might have got lucky though. With 26k, your real close to where the tolerances wont change much between checks, so your loose gap there might not change, will stay loose.
Worst case, before attempting to loosen, I'd just get in hand an adjuster screw and nut. Somebody here might even have one available to offer? I don't have any internal parts to speak off, otherwise I would.
I think I am going to roll with it until the next valve adjust, and I will make sure I have an additional nut and screw on hand, so if I do shear it off trying to loosen it, I will be able to replace it.
Other than that, the valves were in pretty good shape. Not much movement at all this time (last time they were very tight).