I did exactly as you suspect: 55 ton press to shove the stem back to an exposed length compatible with the 550 neck. If I recall, I removed .780 and it fit like a glove.
I had called and spoken with Brandon (?) about making a 550 stem and allowing them to press them in or send to a customer as a threaded or weld-ready unit. He indicated they don't get enough requests for 500/550s to warrant the effort. Shame really, their stuff is so very nice!
I'd also like to modify the underside of the top clamp to better fit the neck of the 550, but in the end, it doesn't really matter as the clamp is secured to the stem and rides on the bearing. But if I were to make a 550 specific unit, I would make that change.
If you pursue this route, definitely gotta do the cartridges and emulators ;-) and dual discs!
By the way, I'm in the midst of making a new gauge bracket for this triple to mount a single MotoGadget ChronoClassic. Analog tach but LCD speedo and info center. If you need something, let me know.
Cal,
I think I've bought into the idea of going dual disc (getting hardware from Goddfrey) and emulators. I will make these changes since they are period correct and unseen (as to the suspension upgrade).
I'm not ready to change up the triple at this point, since it will really deviate from the stock aesthetic. At present, the bike is fairly stock looking, save for the adjustable clubmans, bobbed front fender, rear brake light, brake master cylinder and exhaust. WHERE DOES IT STOP!?
I think that part of wanting to keep it "stockish" is to not break the bank on mods, when I am already going to spend a significant amount on the other 750 and 550, and to keep this one on the road and ridable for me and my girlfriend.
That said, I have just about all the hardware for a Joker Machine front, except the internals and new fork tubes (I'm sure the old ones are extra-crispy under the fork ears). Since the original guages are in such good shape, I want to keep them, so I would likely use the JM bracket if I ever do that swap. Thanks, though! Especially for the 0.78" measurement. Great to know if I go forward with the JM tree in the future! God knows it is difficult to leave our bikes "finished."