Hey folks, here’s the deal, rebuilt the top end because I had 80 PSI of compression and ran awful if at all. 

Have a new piston, and new rings, honed the cylinder and am trying my hardest to get this thing to run to do the break in procedure. I must have kicked 80+ times in this 85 degree+ 70% plus humidity and only got it to run maybe two times for about 2 minutes if that each time. 

I’ve got spark, I’ve got a clean air filter on, newer spark plug, right gap, etc, what should I do to remedy this? It only wants to start with my hand completely twisted on the throttle all the way back. The carb was cleaned a while back but I suppose it could be that? I’m just trying to get it to run to seat the damn rings. Any help would be appreciated. 

So just did a compression test and ugh, it’s showing barely 60 PSI. Surely I’m missing something, new hone, new rings, from the book it seemed well within the parameters of acceptable to hone it down, so do I need to have a larger piston and new rings and new bore? I must be missing something here. Now I know why she didn’t want to run haha!

Not sure where to start except i'm not convinced you're chasing the right end of the problem. Then again how does compression feel on the kickstart. 60psi would feel pretty soft to push through, but are you getting an accurate reading.
You say it will only start on full throttle which has me wondering if it keep running still held wide open but only running at low revs.
If that 'is' the case i'd think something like main jet not in the carburettor.
Or crank seal has popped out left or right side although those symptoms would be opposite to main jet left out.
Or someone has bunged something in the exhaust when ya weren't looking.
Was a trick when young & someone would smack something like a potato into the car exhaust & constipate it then barely run.
Anyway--i'm no help am i.
So it runs but only on full open throttle.
Even at 60psi, if it ran it would rev out.
I know you want to load a video to show us.

Hah RT love your responses man, hmm, so I did replace the shifter side crank seal and checked the ignition side crank seal and it was clean, no oil around it or anything, also when I got it to run for a min or two, WAY less smoke than last time, seemed normal, I don’t have a video of it at the moment, but I can tell you, it sounds like it wants to run with throttle fully open, and eventually it tries to run, and finally does..when it’s running, I cannot let go of the throttle and wants to die under 3k, really wants to float at 4-5K, anything below and it shuts off completely. Carburetor adjustments don’t seem to have much effect at all.

In regards to the compression, perhaps I’m misinformed,  does compression increase once the rings seat? I’m going to tear the head off it and check clearances with gauges and all that this weekend. Either way feeling quite defeated lol 

Kick feels easy enough to run through with your hand, feels about the same as it did with 80 PSI, just seems like I’m missing something, I mean head rebuilds are supposed to have higher compression haha!

Reed valve has all its reed petals i guess. One broken one would play havoc if it was totally missing.

Yep new Reed valves, all intact. When I tear it down ill
look back into clearances, something is definitely not right 

Everybody has different definitions... I just wouldn't ever call honing a used bore and throwing in a new piston and rings "rebuilding the top end".

Unless you had the bore precision measured for taper and out of round as well as piston to cylinder clearance you really never know what shape it's in.

Compression tests are pretty much useless most of the time as well... so you might just be flooded.

You mention the carb was cleaned. Did you use an aftermarket carb kit? The jets will cause issues. Check, no double check your float level, aftermarket float needles are usually of incorrect size and lower the actual float level when set to spec. Also make sure the pilot jet is a Mukuni jet and of correct size and the pilot circuit is clear.

You need to have cylinder and piston properly measured by someone who knows exactly what they are doing. If there is excessive clearance, or the cylinder surface is scored, you will need an oversize piston and rebore.

The idea that crank seals fail for no reason, is very common, but in almost all cases, play in the main bearings, will be the reason for seals leaking. Check carefully for bearing play, and replace bearings if there is any play.