Just curious. Could you run the 41MM FCRs on a M750 or would the 39MM work more effectively? I know you can run the 39 or the 41's on 900's but generally want to run the 41MM. Can you use either on on a 750? TIA!
The answer is yes. Sudco developed the kits around a 750SS racebike and their final iteration was to use 41s. In europe, everyone buys 41s, be it for 750 or 900, figuring that they'll eventually end up with a 944 anyway.
Some very respected tuners in the US think that 41s are "too much" for a stree 904cc Ducati. While I can't fathom how they came to this conslusion, I tell my customers that if they will ever seek the advice of said tuners to buy the 39s so as not to sabotage future tuning efforts with said alleged experts.
That all being said, Sudco will tell you they sell 4 or 5 41 kits for each 39 kit. I have sold a boat load of 41s to people with mostly stock 900s and they love the carbs. I have also sold 39s to people with mostly stock 750s and 900s and they love the carbs.
The carburetor kits ship from Sudco to their dealers allegedly set to a baseline, but I'm careful to verify the float height and screw settings, as these are subject to interpretation and are often not set correctly (or even to the same values between the carbs!).
back to your original question: in order to truly evaluate the difference of 41s and 39s on your bike, we'd need to test both back to back. Given my experience with how it is impossible to "hurt" torque on a 2V 900, I suspect that you may be unable to differentiate between the carbs.