NO!! DONT DO IT!!
Is this a 4 stroke or two stroke. All modern engines are four stroke.
If it is four stroke you dont need to put oil anywhere, except keep an eye on the oil in the engine. DONT put anything in petrol. If you have you need to flush system out. Drain tank empty carb etc. If you are going to put something in the fuel then it needs to be redex or similar. This can clear dirty carbs.
These Chinese bikes use soft metals.
It could be one of two things.
As you say the carb or if it is four stroke, which it probabaly is, then the valves tighten up and as a result you wil have problems starting and running.
I would get valves adjusted first. As Adam who comes on here quite a bit and is a bike mechanic by trade says this is a very comman fault. You will need a manula to be able to do this properly
Good Luck
bb
August 2010