Why so much smoke?

If the Oil seals were bad it might run terrible but it wouldn't be smoking.

2 engines with the same problem suggest something in common with both engines.

Have you recently mixed up a fresh batch of fuel?

Smoke suggests Way too much Oil.

Are we talking smoke as in, you can see the exhaust, or Smoke as in you can't see 10 feet!

I used a one liter plastic bottle of fresh fuel 50-1 Shell 2T mix siphoning into the carbs until I fitted the refurbished Mikuni fuel pump which was about the time the smoke problem started.

The smoke filled the my shop within ten seconds and smelt like burning gear oil bringing tears to my eyes so I tried it outside running it for 5 minutes but the smoke never ceased.

With the 447 I drained the oil from the gearbox thinking it might be sucking in gear oil through a faulty seal or something but it still kept smoking as well.

I will go through the two Bing carbs and give them a good clean and see if that makes any difference I'll also disconnect the fuel pump again and see if that has any effect.

It just seems strange that it ran beautifully after instant starts and then this :(

Thanks for your input so far, much appreciated.

This is out of my area of expertise but, if two engines started having the same issue and you are smelling Gear Oil in the exhaust (It stinks!) then logic would say that you have a batch of fuel mixed with gear oil instead of Two Stroke Oil.
It Happens!

Please post some pics of your installation, it might help identify your issue. The two engines are not the same, the 582 is a rotary valve and the 447 is piston port. They both require lubrication supplied through premixed fuel or by an oil injection pump. The source of the smoke coming out of the exhaust is the oil that is going into the intake. The lubrication oil for the rotary valve drive on the 582 should be the same oil that is being added to the fuel. If the exhaust smells of gear oil the only source of that oil is the Prop speed reduction unit. 

Problem has been solved, my son flys a foot launched powered paraglider.

I asked him to get my fuel drum filled up the next time he goes to the gas station for his own fuel.

He returned with the 2 full drums but never told me he also had the 2T oil added.

He uses 25-1 and thought I used the same so when I added my 50-1 there was way too much oil and plenty of smoke.