I should've known. There's a reason why she's called "Old Faithful." Whenever I expect the worst and try all manner of things (like buying coils I didn't need, although it is nice to have a spare set) the problem with the CB turns out to be something simple.
I tried mounting the new set of coils, thinking I had the loss of power at high speed licked, but then it happened again. I double-checked the timing—perfect. I rechecked the valves; exhaust a bit loose, by design (as I had read "better loose than tight"), but nothing was amiss.
On a whim, I pulled the slides, with the idea of looking for any tears or pinholes in the diaphrams. This was easy because all you have to do is loosen the intake and air filter boots and rotate the carb so the top can be taken off—no need for complete removal. I pulled the left one; nope, the diaphram was perfect. I pulled the right one.
That's funny, it should have easily slid out, but instead when I reached my fingers in and pulled, the slide would not budge. I pulled a little harder and out it popped! I knew something was wrong there, but I dutifully checked the diaphram on this carb, too—perfect also.
But what to my wandering eyes should appear but a bunch of gunk on the side of the slide. It looked like a thin layer of boogers smeared onto the side of the slide. I know I had not used the slide to wipe my nose, I swear, but I had neglected to check and clean them when I did the rest of the carbs recently. Something on the bench must have stuck to the slide, and I never saw it. So, what had happened was that I had basically glued the slide into the right carb. A slide glued into place does not bode well for performance.
I slathered some Strong Arm miracle elixir onto the slide, being careful to avoid the diaphram and wiped vigorously until all remnants of the boogers were gone from slide and carb. With her nose clean, so to speak, I reassembled the carbs and fired Old Faithful up. A quick ride east and north out of town, reaching illegal speeds, proved the bike now performing as it should.
The left sides stutters a little on idle, but give her any throttle and off she'll run like she means it. The idle stutter is minor and, I am sure, a result of a slightly dirty main nozzle that is stuck, perhaps eternally, in the carbs. My repeated attempts to dislodge this nozzle for proper cleaning have all failed. I may have to resort to buying a sonic cleaner and submerging the carb to clean this up completely. But for now, I can live with minor irritation of the less-than-perfect idle.
Game on! Looks like Old Faithful will once again enjoy a ride through the Blue Ridge.
"Ride Your Own Ride."