I rode several 2-cycle bikes back in the day. And tore them down several time just to see what things looked like. A ring job on my Kawasaki triple took less then an hour.
The thing to remember is that 2-cycle oil is designed to burn during the combustion process - and to burn very cleanly with an absolute minimum of ash. 4-cycle oil is designed to RESIST burning, even at high temps - and when it does burn you will definitely get a lot of ash and varnish.
At one time I also had a 2-stroke jet ski and noticed that Yamaha sold a 2-stroke oil for air cooled engines and another for water cooled engines.
So, IMHO you are crazy to even consider using 4-cycle oil in a 2-cycle engine. Unless you LIKE having the rings get fouled and start sticking. In the big picture, the cost of using the right oil is minimal.