a little trick for testing the effects of a smaller main jet is to add more 2-stroke oil to the mix. It makes the bike run leaner.
At what point does adding oil no longer lean the mix? By definition there is no such point. More oil = less gasoline mixed with some constant amount of air.
At what point do the side effects of too much added oil prevent the possibility of damage due to a lean mix? I guess you have to test it and find out.
I'd guess there are at least two reasons Amsoil can make the claims it does.. First off they are not talking about 25 year old moped engines. Secondly they are trying to sell a product.
Their resoning is that since there are no solvents in their oil, you can use less.. However logically speaking, if there are no solvents you are not necessarily using less.
A 50:1 oil-type is half solvents and you need 1 ounce. (1/2 ounce is oil)
If you remove the solvents and go 100:1 you need 1/2 ounce.
So you are using 1/2 ounce of oil in either case.
If you trust them enough to use their oil at 100:1, be my guest and please report back here with the results.