Nightcruiser, I did not mean to raise your ire. Believe me, I appreciate all your help.
I'm a little mechanically inclined and like to tinker, so I'm embarrassed that I got this backwards.
I started with 50:1 and switched to 16:1 on the day the problem started.
You didn't raise my ire, I just know we can't help you unless you give us the real details of the situation.
IMHO 50:1 is pretty light on oil for conventional 2-stroke, even for after break-in. There are differing opinions, I like to stick to 32:1 for my regular mix, my motor runs well and gets plenty lubricated.
As others have said, 16:1 is a LOT of oil to run and can make the motor run like crap (contrary to what the manual says, most people never use that much oil), so what you are experiencing is kinda par for the coarse. It's hard to tell if riding at 50:1 during break-in has caused you any trouble from what you have posted here, generally trouble would be pretty obvious and catastrophic, so you're probably OK if you still have good compression and she isn't (or didn't) make any horrific noises.
I am wondering how much of the 16:1 mix you burned through after you changed to that mix? If it was a fair amount then you might try moving to 32:1 mix and see how she runs with that. I would also check/re-torque the head bolts, make sure the air filter is clean, fuel filters are clean, carb is clean, replace or clean the spark plug (upgrade to a better plug if possible). You may need to do some tuning to your carb to make it run properly (which is not related to your mistake with the oil mixture, it's just par for the coarse with these little HT motors)
So give that stuff a try and see how you do and report back, hopefully we will get you back on track and you can chalk it up to exprience.....