Well, my guess would be:
first, the early 750F uses 6 friction plates and 5 steel, with a 6th double-steel plate that had tiny springs between the steel plates. This was often replaced with the extra-thick Gold Wing GL1000 "Clutch Plate B" (still available) because the rivets holding these 2 steel plates together could get loose, letting the clutch rattle like mad.
It looks like someone tried to mimic the spacing caused by this double-steel plate with some copper (brass?) plates instead. But, it also sounds as if there are too many friction (cork) plates, too. There is often confusion about this, as the 1976 bikes changed from the 1972-1975 versions which DID have 7 cork and 6 steel plates. The early "F" was a slightly different design. The top plate is also a special one, with slant-cut cork blocks on it and wider tabs at the outside edge (you should notice the clutch basket has slightly larger slots for this top plate).
If the incorrect number of plates is used, one of 3 things will happen:
1. If not enough thickness for the whole stack, the clutch will slip, or may not engage at all when tightened up. This happens when modern, similar-looking, but too thin, cork plates get used. The superbikes use the exact same SHAPE as our plates, but they are only 0.132" thick new, and ours are supposed to be 0.141" thick (they are worn out at 0.136" thickness). Someone may have found themselves in this situation and tried to 'fix' it with those brass plates?
2. If too many plates, or too much thickness, the stack will bind the springs and the lifter cannot separate the plates. Keep in mind this is a wet clutch, so when you assemble it you MUST dip each plate in oil before installing, or they will NEVER break loose to slip when disengaged. They will continue to be wetted when the oil pump starts up, being oiled by the hollow mainshaft.
3. If the stack is too thick and the hub is the 1972-1975 type, the top plate may crack when the screws are tightened down. This happens more than we would like...
