Consult the recommended dilution ratio on the bottle of two stroke oil you are going to use. Always dilute at that ratio and you won't have any problems.
The manufacturer will recommend a ratio, but this is providing you are using the manufacturers own recommended oil- which could be 100:1 50:1 25:1 or even a 20:1 oil. Logically the engine doesn't have a clue what ratio you are putting in, so unless you are using the manufacturers recommended own oil, any ratio recommended by the manufacturer can be disreagarded.
The engine will run exactly the same even if you put neat petrol in, but obviously add too much oil and it will smoke and oil up, and too little oil and excessive engine wear leading to eventual seizing will occur.
If the oil you are deciding to use states 50:1 on the bottle, then dilute it at 50:1 and this will give your engine the correct protection.
A 100ml bottle of 50:1 2-stroke oil is perfect for adding to a 5 litre can of petrol- shake it up and it's mixed.
If you don't require 5 litres, then you can easily obtain a 2-stroke mixing bottle which is suitable for gauging the correct dilution ratio a litre at a time, which is a more suitable quantity for home owner use.
pleasant, October 2008