Just changed out the 10-40 version of Valvoline MC oil from wal mart (3.98/qt) in my 550 after a couple thousand miles.
Shifting and clutch action was fine.
It is labeled JASO MA, which I think now is a combination of MA1 and MA2 specs.
The constant change of specs and additive packages is enough to make your head spin!
The best "feeling" oil I have used as far as clutch and tanny is concerned, was Mobil 1 15-50 full synthetic car oil (about 10 years ago), but who knows what's in it now!
I'm now trying Rotella T 15-40 diesel ($12 and change/gallon) from wal mart, which other boards are high on. It's also MA listed.
I've been using that 15w40 diesel in the break-in oil of the 550 engines I recently rebuilt. For short-haul (non-Interstate touring) riding it should work OK.
The Mobil 1 15w50 worked well in my 750 until I hit the hiway for a while (70-80 MPH), then it became thin enough that the engine was heating. Long ago they made a 20w50 in a similar formulation, which got me started on the 15w50, but eventually it dissolved the sealant on the gaskets and began weeping out (slowly) everywhere. The 500/550/400F/350F has O-ring top end gaskets, so this wouldn't be as big an issue as with the 750's paper gaskets.
So far, I am not impressed with this Valvoline in my 750. When cold it's OK, but when hot I have trouble with shifting into 1st gear (that's a new one! Never had that before) and it hangs partway into 3rd unless I'm REAL deliberate with the shift. It has about 100 miles on it so far. Next I will try adding some ZDDP to see if it improves: if so, we'll know where the issue lies...
This morning I was embarrassed in traffic when a light turned green and the engine stalled when I tried leaving: it seems someone stole the gas out of my tank last night, leaving just enough to barely cover the MAIN pipe until I got to the end of the street. Switching to RES solved it, but I only showed 53 miles from 3.4 gallons? Nope, someone stole it: this is Colorado these days...