Could be an exhaust leak or oil burning off.
Pull the header and check for black carbon then replace the gasket

Looks like burn off , head plug leaking oil. Unless you just washed it ,then it’s steam. Steam or smoke ?

I see your gasket.  It's a spiral wound gasket.  You can see the end of the spiral in this markup.  Looks OK to me.  I think you just have an oil leak (probably head plug as previously mentioned), or residual oil on the engine and head pipe.

The interior of your exhaust port looks pretty wet.  That area is typically dry with a coat of black carbon, sort of like black velvet.  Yours looks like it is oily.  I would run it for a while and recheck.  Is there white smoke coming out of your tail pipe?

I'm following Gary's lead on this one.

The stalling sounds like the classic failed fuel petcock.  It is a common problem on these.  It is also the main reason gas will get mixed into the engine oil and could also explain the wet exhaust port DBM pointed out.

Is it a stock petcock?  

Also, when did the problem start?
Is this a new problem? 
How old is the bike?  
How long have you had it?
Did it sit for a long time?

The smoke could be from the oil leak (things DON"T look wet) or gas in your oil.  Either way, your video clearly shows an exhaust leak and there appears to be evidence of exhaust blow-by in your pictures.  The smoke is being pushed away from its source.  

The idle is not alarmingly low.  I think 1100 rpm is spec and that equates to 550 bpm.