This is how I set the wheel with the new MOA.
Once when I was plying yarn rather fast and it was a longish session... at one point my other Matchles got somewhat hard to treadle... what has happen? It turned out that I had a black build up, small amount near the orifice, from the metal-to-metal contact. So the front part of the flier was pretty warm to touch.
Removed the flier, cleaned and re-oiled everything. All fixed.
I did not look at the orifice side at first I thought maybe something got caught in the wheel some place else.
Hope that will help to troubleshoot some treadling to someone else.
Re-oiling the bobbin-flier when spinning gossamer: I clean and re-oil every time I change the bobbin for lace weight. when I spin fine gossamer re-oil and clean the bobbin more often, I like it very clean to have it very smooth going.
Maybe alter I'll add some photos for the Matchless with the old MOA and SR in ST for the gossamer yarn spinning...