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Good morning, all
I did some further investigating last night on this interference issue.  Using my list of items to look over, here’s what I’ve found.  Rod with “mushroom head” that pushes the pressure plate sits all the way down with a “clink” as it should.  If it weren’t, I’d think that in turn the pressure plate wouldn’t be able to sit properly as it is.  Here’s what I did last night….

• find & review service manual – done and good to have, but didn’t tell me anything I didn’t already know.
• measure all remaining discs, plates, & cushions – All pieces verified and measure as they should.
• check actuator adjustment – adjustment was perfect.  Screw turned in till contact with rod then backed off ¼ turn and locked down.  Basic stuff
• reassemble according to manual / parts diagram – done but manual not needed
• match reassembly to new skydancer46 photo (if possible) – wasn't necessary, but thank you
• add wet paint (or any better suggested marking material) to pressure plate, put cover on along with gasket and hope that clutch activation leaves a mark- Succes!  Sort of.  The exercise confirmed that the pressure plate center is contacting the small nub on the inside of the cover!  See pic.

Now, where to go from here?  I’ve got the problem area specifically isolated.  Now to find the cause.  Given all that I’ve done, the only two items remaining (that I can think off) are to extract the actuator side push rod, measure it, and to compare to the specified length -which isn’t in the service manual.  If someone can post that, I’d appreciate it.  However, consider this…. for discussion purposes, lets say the rod is found to be 2mm too long.  Why would it matter when the extent of the movement of the rod is completely controlled by the ability of the actuator to advance it?  If the actuator is designed so that it’s maximum limit to push the rod is 4mm of movement, then regardless of the length of the rod, it’s only going to move 4mm.  And if the adjustment at the actuator is set correctly (screw backed out ¼ turn  from contact) any extra length would be nullified.  Am I wrong?  Nonetheless, I will measure it and compare it and post the length here.  I am truly suspecting that the side case has somehow gotten deformed ever so slightly.  I sure can’t see it.  But, logic tells me that if I grind that nub down a couple of mm’s the problem will likely be solved. Thoughts?

ADDITIONAL: I can't post the pics!!!!  

Follow where all the screws are in this link.
It's possible any dowels are rusted in & just hanging on.
Could actuate the clutch a little at a time on the clutch lever & tap around the cover to get it to move out until you run out of actuator movement but should help.
I don't see the dowels drawn there--only for the other cover but i'm sure there should be two & will be on both screws #5 if you can follow them--one top one bottom & sort of inline & supporting the actuator to stay inline with the pushrod.
Those two screws will be longer because of the dowels.

www.partzilla.com/catalog/yamaha/motorcy...125c/crankcase-cover
Also if you look through the inner cover you see a cut out which has a slotted rubber thingy.
They jump out then hide under the bench so be careful. I'll post a link to that as must be in the crankcase pic.
www.partzilla.com/catalog/yamaha/motorcy...c/cylinder-crankcase
Number 12

"You might report how far the pushrod is sticking out of the end of the shaft?  IIRC there's normally very little to no gap under the head of the pushrod and the end of the shaft"
 Mark - not following.  The actuator side?

Ray - clutch operation has been viewed with side cover off and works beautifully.  This is why I'm focused on the cover being the culprit..  When it goes back on, the clutch movement binds.

Nonetheless, I will be reviewing everything that's been mentioned to eliminate all other possibilities. 

 "...Just that more than once I've seen clutches slipping because the freeplay at the handlebar lever is correct but the "internal" freeplay at the engine is non-existent."  Thank you Mark.   I will be going back to this to be sure all bases are covered - but I can't see me putting this together and not addressing the adjustment.  I do have a couple of mm of play at the lever before feeling any resistance, but I know that's not the whole story.  it'll be revisited.

Skydancer - I've confirmed my cover is the same as shown in the cmnsl picture.  More on this in a bit.

Additionally, while home for lunch I took sample measurements.  I didn't have time to do every component.
"heavy plate"  3.22mm
spacer  2.3mm
rubber cushion  3.04mm
friction disc  3.04mm
plate  1.58mm

I'll look for the manual on the site.  Hopefully I'll be successful.  But honestly, I'm thinking there's probably nothing there to help me.  But I'll give it a review.

My latest idea is what can I use that I can put on the outer most edge / perimeter of the pressure plate and the center point that'll remain through a quick reinstall of the cover and will leave a mark upon contact with an interfering surface?  I'm thinking maybe a dab of single stage paint?  That tends to take awhile to dry up.
I'm wondering if there was ever an impact on the cover that resulted in an ever so slight distortion - even though I can't see it.
Also, regarding the cmnsl cover, I'm wondering if I could get them to lay a straight edge across the backside of the cover and use a caliper to give me an accurate measurement to the that little "tit" that's dead center.  I'd do the same for comparison to help prove out the possible distortion question.   I keep suspecting it's involvement.  

Skydancer - your posted picture looks pretty much the same as mine when assembled.  Thank you.  Perhaps another pic from a 90 deg angle that'll show the true relationship of where the backside of the pressure plate is in relation to the leading edge of the clutch basket?  If you can without any bother.

So recapping....

• find & review service manual 
• measure all remaining discs, plates, & cushions
• check actuator adjustment
• reassemble according to manual / parts diagram
• match reassembly to new skydancer46 photo (if possible)
• add wet paint (or any better suggested marking material) to pressure plate, put cover on along with gasket and hope that clutch activation leaves a mark

Anything else I should consider for this evening's homework?

Thanks fellas

If we are talking about the small needle roller bearing inside the gearbox case next to the clutch rod actuator/pivot, i broke two small pullers and ruined the bearing trying to get it out.
A machine shop had to do it for me.
Mike

Push lever = clutch actuator arm? , Small bearing puller and some heat, is it bad ? if not leaving it might be an option? 

Talking balls--umm--if it wasn't there i doubt you could adjust things for the clutch to separate but could be wrong. It is a 3/16 ball just looking at partzilla so i guess the adjuster on the pressure plate could take care of that if missing but i'd expect adjuster to be close to dissapearing in the locknut. Even so, the clutch would still separate & work how clutches do-- but the pushrod ends wouldn't like not having a ball to revolve on. Well one half revolves & actuator end i guess doesn't revolve when being 'actuated' but would revolve- 'all of it' when clutch released. Confused?-i am lol.