Sorry Na i'm wrong. Here's a video showing it same as yours. Ignore my rant above. I'll stand in the bad-boy corner lol.
Give it a tow down the road or spin it up with a powerful drill. I've done that with a 100cc & you might get lucky providing the mag nut is super tight as it's a constant drill turn not an impact hammering movement. Need two hands on the drill. Better still get some start roller. [wish i had some at times].
Vid link & not keen on his removal puller, but it worked.

Seal is flush, picture is a bit misleading, vacuum test was done in on the breather tube with a brake bleed vacuum pump per the question in a prior post.

I don't know if it's YouTube or TikTok or something that has created a trend of unconventional techniques... 

I have mixed feelings...  I'm all for finding other ways to test and repair...  RT325 and other members have figured out some genius ways to do things...  like building a homemade press mostly out of scrap to rebuild a crankshaft or a jig to support the frame to remove a stuck swingarm bolt. 

The key point is that these alternative methods actually work and that they "do no harm".  Not using the correct flywheel puller for example very often and very easily does significant damage to the stator coils.  I've seen bent and broken flywheels.  (It's not really worth the risk, best to spend $15 for a good puller.)

I don't know the exact details of vacuum testing the clutch/trans was done...  I imagine what you're saying is that you created a certain amount of vacuum and it took 3 minutes to go back to zero?  It's not a bad idea...  but there are so many places like the tach drive that are not likely to be air tight so not sure there's much value.  Properly pressure/vacuum testing is not that hard and you'll know for sure if there's a leak and where it is. 

There's a guy on YouTube that does satirical humor videos on motorcycle repair...  the sad part is many of the "serious" repair videos and wiki pages are just as ridiculous in terms of actually working.  And people actually try to follow them. 



There are tested and proven procedures to set timing, check for air leaks, etc.  With a lot of experience, sometimes someone comes up with an alternative method that works just as good.  Most of the time is best to stick with time-tested and proven methods.  They usually aren't that difficult.  

This is not "rocket science".  Stick with checking and following the basics...  no matter how much you think "it can't be that" or "it has to be this"...  and these old bikes will run.  Trust the proven processes and follow the steps. Be honest about what you've actually done and report as many details as you can.

That's more than enough unsolicited advice for the year...  good luck, I hope you figure it out soon. 
 

I've forgotten how it all began. Started farted slipped & fell [racehorse].
Looking forward to hearing she runs.
Wonder if the stator coil is weak & not good enough for the plug under comp.
Close the plug right down to something ridiculous like under 20thou.
Set point by loosening the screw & re-tighten at 1.8btdc so touching but just ready to part.
Make sure your throttle is closing as it should. Choke won't suck if throttle not closed.
Piston in the right way--holes at the inlet side.
Reed block in place--no broken off reeds. Gotta go!!
People used to bring bikes into work & the favorite customer saying 'was'--i've done everything so it can't be much [yeah rite].
'Or'--it's only a two stroke so can't take much to fix it.

MarkT that’s Hilarious someone will try it 
​ ​​​​​  

LMAO!!! I suspect that just any old spoon won’t be of tolerance….
Sneezles61

****UPDATE******
it started!!!! (on starting fluid).  to get to that point i pulled the head inspected to be sure i did not install piston backwards, it was good.  I trimmed the coil wire back a bit, it was a new coil but a bit long.  I also replaced my points and my plug.

then low and behold it fired up on canned go-go juice.  put some gas in and it instantly flooded out.  Got it started again then it flooded, i am now out of new plugs so i am having a beer.

Good news is i am NOW chasing a carb issue which is far easier to deal with.  Thanks everyone for the help on this.  Pic of my ultra worn point foot below.  

That's good, we're getting somewhere!!. Flooding as in pouring out or?. Got the little Oring where the bowl seals on to the needle jet [jet setter]. Sounds hopeful for sure.

Take the keyster brass out and put your original brass back in clean. Keyster is notorious for miss labeled brass ware as RT325 says check the oring too

Sounds good, I plan to swap carbs with my eBay one to see if I get get things going and finish other checks like the oil injection.  I have enough parts that hopefully I find the right combo.