Joe,
Sorry I did not include my email address in my previous private message - thought it would show up automatically at your end.
Thanks for your explanation of the evolution of Commando clutch plates. I was not aware of the early bonded steel plates used in Commandos. I was under the impression that there were only 2 types; the thick solid fiber plate (4 ea used with thick [06-0745] pressure plate), and the thin sintered bronze plate (5 ea used with the thin [06-3768] pressure plate). The Surflex clutch pack I had in my '70 Fastback was not the original equipment, but rather a replacement recommended by a pal. As I recall the Surflex plates were constructed of a friction material bonded to a steel plate. They were much thinner than the original solid fiber plates, closer to the thickness of a sintered bronse plate. I'm embarresed to admit that I don't recall if my Surflex clutch pack in the Fastback was set up with 4 or 5 friction plates. I seem to recall using the thin pressure plate and perhaps an extra plain steel plate to get the diaphragm in it's sweet spot, so the clutch pack probably consisted of 4 friction plates, 4 plain steel plates, and a thin pressure plate. What I do remember is that my clutch performed flawlessly - easy pull, always complete & total release, never a klunk going into gear from a stop (chain didn't even snatch), the shift from 1st to neutral was the same as if the engine weren't running, and it never slipped, even with high RPM shifts.
Since I am not familiar with Triumph clutch plates, could you please elaborate on the 06-0749 that you provide these days. Are they NOS items from early Commando production or are they new items supplied by Surflex? Is the friction material bonded to steel or aluminum plates? Could you provide the nominal thickness of the 06-0749 plate?
All this may be a moot point now. Over this past weekend I replaced the lube in my Mk III's primary. After draining the old lube I reinstalled the drain plug , poured 12 oz or so of mineral spirits into the primary and ran the engine for a few moments on the workstand. The engine was shut down, the spirits drained, and the process was repeated, this time actuating the clutch a few times and putting the machine in gear while holding the rear brake on. The second batch of spirits was drained and 7 oz of ATF was added. Since doing this procedure the clutch seems to be working much better. I was not experiencing slippage before but it was very difficult to find neutral while stopped at a traffic light. I've gotten into the habit of finding neutral while coasting to a stop, but sometimes I do forget and all seems better now.
Thank you and all the members of this board for your patience. I would appreciate the details on the Surflex (06-0749) plate when you find the time.
V/r
Joe in St Louis