Today - all day - was Valve Adjustment Day. I was significantly overdue for it, from a milage standpoint, as a valve adjustment was called for at 7500 miles, and Zoë's just over 10k now, but I figure: better late than never. It seemed like a pretty time-consuming and technically demanding task, and so I called on the infinite knowledge of the S-T.n folks, as well as my Suzuki and Haynes service manuals, and figured I could probably slog my way through it.
The time-consuming part of this service is not the valve adjustment itself, but rather the disassembly required to get the valves exposed. In short, the seat, fuel tank, spark plugs, "breather," left-side fairing mount, and a variety of assorted hoses need to be removed and set aside before the valve cover can be taken off. Getting the cover off is also extremely challenging, as long as the engine's within the frame, as clearance is extremely limited - it tends to catch up on the cam chain assembly, and took some finagling to get removed.
Here's a pic of Zoë sans seat, tank, and rear side panels.


...and once the parts are all off, they should be set aside in a safe and relatively clean place, as the task is only beginning... Here you can see the valve cover to the left; its bolts have been replaced so none of them go missing. Above is the tank, with vent hoses still trailing from it; fuel and vac hoses were disconnected and remained on the bike. The aluminum box in the middle is the breather, which bolts on to the top of the valve cover; I had to remove it in order to get the valve cover out of the frame. Plugs are lined up at the top of the shot, in cylinder order.

Here's a shot of the innards of the engine, beneath the valve cover. You can see the dual camshafts, one on each side of the shot, and the cam chain running left to right near the middle. The #1 and #2 cylinders are shown, #1 closest to the camera. The spring-lookin' things to the left of the cylinders are the exhaust valves for #1 and #2; the intake valves are hidden by the camshaft in the right of the shot.

More valve porn. This is from the other side of the bike; you're looking at the #4 and #3 cylinders here. #4 is closest to the camera. Intake valves are apparent on the left side of the shot, and the exhaust valves are on the right.
(at least I hope I identified the intake valves vs the exhaust valves correctly, or this adjustment was a very, very bad idea.)

After exposing the valves for adjustment, the cover needs to be taken off the signal generator, on the right side of the bike. Here is a shot inside the signal generator. Using a large (19mm) wrench, one rotates the cams using the big nut inside the signal generator until the cams are properly aligned to allow valve adjustment. At a given cam position, you can adjust either #1 Intake and Exhaust / #2 Intake / #3 Exhaust, or #2 Exhaust / #3 Intake / #4 Intake and Exhaust, so the cam is set, the valves in a given set are checked, and then the cam is advanced and the other set adjusted.
On the Bandit motor, the intake and exhaust valves are set to different values; .004 - .006" for intake, and .007" - .009" for exhaust. The actual adjustment procedure is pretty straightforward; measure the valve gap with an appropriately-sized feeler gauge, and if adjustment is necessary, loosen the locknut with an 8mm wrench and set the setscrew with the Ghetto Valve Adjustment Tool (a square-drive screw in the end of a dowel, made by yours truly because no local shop had the Suzuki tool in stock). Adjust, re-tighten, check, and move to the next valve. The only reason this was time-consuming was that I adjusted all 16 of them, and then repeated it because I wanted to make sure...and found that I'd adjusted every one too loose. No idea how that happened. So I repeated it twice more to be certain, and torqued down all the locknuts tight. I hear it's bad news if one comes loose when the engine's running.
I did the measurement by sticking in the appropriate-sized feeler gauge - I used .005" and .008" for intake and exhaust, respectively - tightening the locknut down, and then adjusting to juuuust a bit of pressure on the gauge. I'm not sure if this was the right way to do it or not, but when I went back to check after the fact I checked both the size I originally set it to, and a slightly larger gauge (.008" / .010"). As long as the original size still fit and the larger one did not, I called it good. If there is another method, I'd love to hear about it.
All that was left was to put everything back in reverse order. I sprayed down the valve cover with contact cleaner to make sure there weren't any little bits of gravel waiting to work their magic on the inside of my engine, spread some liquid gasket on the appropriate junction points, and buttoned everything back up.
She runs. I have no idea whether I made anything better; pretty much all the valves were too tight, initially, and now they're spot-on. When I lit her up after the adjustment, she went right into a very smooth idle, where normally I'd have to use some choke to get her running. She also used to hang at higher RPMs for a moment after coming off the throttle, when in neutral; in my short run this evening, I didn't see that, so I'm hopeful that I've tuned her a little bit better than she was. But that remains to be seen.
While this was a time-consuming task (probably 5-6 hours all told), it wasn't a particularly hard one. If you've got a valve adjustment coming up, give it a shot! I feel a lot more comfortable about exactly what's going on inside the mill now than I did before.