We have oils with determind flash points, at which are more clean and free of carbon deposites etc. A proper clean burn.
Here is some forum stickies. http://motorbicycling.com/showthread.php?t=24873
Wanna say from my understanding. Too much oil can fool some one with their plug reading somtimes?
16 to one will lean out a air fuel mix as there is a little orfice the gas has to push through ''jets''. Resulting in less fuel from the fuel being thicker and the gas being deluted with oil.
However the flash point of the oil is heavier and the bike will soot up running with less power IME. You will get deposites in your motor and plug.
You want Air cooled two stroke oil. Not a water craft kind as flash points are designed differantly. Water cooled motors run cooler. From everything I have learned.
Now wanna say good oil at the manufacture's recommendation is a place to start . If one says 50 to one going 42 to one is nothing like 16 to one lol.
All this rymes with proper jetting. Then the engine will develop good power and run clean!