Well, after 2 days of having my clutch lever zip tied to the handlebar, my clutch still seems to be stuck. Even after rocking the bike in gear, the clutch will not disengage.  I'll leave it tied in hopes at some point it might disengage, but I'm thinking I will try to start the bike and maybe some of that vibration might help.

As for my previous posting where I said when depressing the clutch lever, it feel "normal" to me.  Is it possible that it feels "normal", but it isn't actually functioning properly in the sense of disengaging the clutch? I feel certain the plates are stuck, but how might I know if they are free and the lever/cable is not working?

Also, how safe is it to shift thru the gears without using the clutch?

I think your best bet is going to be to drain the transmission, take off the right side case cover, and take apart the clutch so as to separate the plates/discs and clean them individually with brake parts cleaner. Reassemble and then refill with new, quality fluid rated for wet motorcycle clutches. It's...not...that...hard.
Anything less than that, and I believe you will continue to have this problem if you let the bike sit for a couple of days, especially in cold weather. I know this because I have done the above to most bikes I have, but there is one I have not taken apart and cleaned, and it's the only one that continues to hang up and need to be "rock and rolled" every time I want to ride it after sitting for a few days.
Edit: No, I don't think there is anything wrong with your clutch lever/activator/cable! That's good news, at least.

Yes clutch will feel normal on the lever even when plates are glued together. MOTHERSBAUGH above is right but maybe i've been lucky & especially on my rat bike HT1 as you can see its been hibernating outside for years but i just started it & rolled it forward sitting on the seat & into first then second then off & on the throttle with lever pulled back to the bar--short version but worked. Then gave it a good workout. Good habit to tie the lever back overnight if it's a dodgy clutch that's already been stuck up. New plates & won't need to worry about any of that.

After unsticking, I just slip the clutch a couple of times good.  Never had one re-stick again right away after that.

I'm with RT325, before taking the side cover off I'd go find a dirt road with some downhill and start it in neutral, get it rolling and pop it into second. Keep the clutch lever in and ride around a bit, it'll loosen up quite soon. Then slip the clutch a bit like MarkT says or it'll lock up again - of course you can just rinse and repeat if you have the energy to start in neutral, push it up to a few mph and put it in gear and eventually it'll take care of itself - if there is no elevation where you live, start with this too

That said as far as while not running, the clutch on my '72 CT2 still drags or doesn't release when pushing it around in gear with the clutch pulled in, especially after sitting a while. Even after new plates and 2,000 miles. Seems like this isn't too uncommon.

All of the information I've received is great! Like I originally said, I'm trying the simple things first, then graduating to the tougher solutions if simple doesn't work.

Mothersbaugh, I have a few questions after looking over the clutch schematic. If I decide to go the route of cleaning the individual plates, when I remove the right side cover, is there only a single screw holding the compression spring and pressure plate in place? Do I need to remove the entire clutch basket, or will I be able to remove the plates after removing the pressure plate? Are any components under high pressure I should be aware of (I don't want anything "popping" out and hitting me)? Will cleaning the existing plates be enough, or since I would have the plates out, should I consider replacing them?

Since you have apparently done this before, I will go with your guidance. Thanks!

Jimbo....I'll do what I can. Looks similar to what I've had apart before, AT's and CT's. There are 5 bolts/springs holding the pressure plate on. You need to get all 5 off of there to remove the plate and get at the discs and metal plates in the basket. You will need a means to hold the basket still while you work on those bolts. DEET sells a wonderful tool just for that: an old clutch plate (#6 in the partzilla schematic) with a bit of rod welded onto it. Beware of just sticking a large screwdriver through the basket; that may find you breaking off one or two of the this side prongs of the basket. Some use a strap wrench; others find that sticking a penny in the gearing between the crank and the clutch itself works. But you may be able to get the 5 bolts broken loose rather easily one of those ways. If I remember right, you do not have to take the clutch basket off to pull out all the plates once the pressure plate comes off. And the clutch basket itself really needs to be held tightly for the removal of the big-azz nut (#15) in its center if you are removing the whole basket. (Someone will correct me if I am wrong.)
While you have the bolts and springs out, check the springs for the minimum length in the manual. Then make your replace/reuse decision on the fiber plates' condition and thickness, again listed in the manual.
Take pictures when you get in there. Remember the order of metal/fiber. When you have the plates apart and cleaned, show the forum their condition in pictures, and guys will tell you what they think. Really, they don't cost that much. The metal plates also should be cleaned and inspected for wear. They'd run you a bit more.
When you put it back together, use new fluid, of course. Something specifically designed for wet motorcycle clutches. I'll bet there are 6 or 7 "oil threads" here where guys will reveal the magical fluid that wins them races; no need to ask again. Just search! Some use SAE non-detergent generic oil, some use ATF, some use Rotella (if I remember correctly). Just make sure it's non-detergent and designed for wet clutch applications.
Inspect your right side case cover gasket. If it looks if-y, get a new one. One tip I used from someone here: grease a new gasket; it seals better. Nothing heavy, just enough to swell it a little and seal better than dry.
Really a pretty easy job. Was the second thing I did 11 years ago when I bought my first Yammie, a CT-2. Cleaning the carb (5 times) was the first.
Check back with questions.
Edit: also a good idea to check your crank seal if you have the basket off, which you don't really have to do.

This is what you're looking at if you 'realy realy' decide to go in. I hate work & creating problems so tend to go the easy route first.
Here's what you'll be looking at although looking from opposite angle & facing the pressure plate.
www.partzilla.com/catalog/yamaha/motorcycle/1970/ht1/clutch

Holding tool is only needed if you have to pull the inner basket... 

The 5 pressure plate screws should come out easy and all the clutch disks can be removed and replaced without having to mess with the holding tool and the big nut holding the inner basket.

It's a very easy job.  Worst part might be removing all the old cover gasket if you need to replace it.

Anyone know if you can see the clutch from the oil filler with the cap removed?
I know you can on the RT1 (I know a considerable bigger engine).
I managed to separate the friction discs from the metal plates on my RT1 by very carefully prising/coaxing them individually with a clean flat blade screwdriver through the oil filler hole, with the clutch lever clamped, I rotated the engine slightly to get to the next gap in the basket and so on.
Shyted has a HT1, I'll message him tomorrow as it's a bit late here, and ask what's accessible from the oil filler hole.