This is the place for moped related questions.
Sometimes it may take a little time till someone notices you.
I have heard it said that the worn oil pump will allow oil to seep into the engine and make it smoke like the devil for the first couple of miles.
If there is enough oil in there it may not even run well or at all.
I have heard people say to remove the spark plug and kick the daylights out of it till it stops spitting oil out the spark plug hole.
I have not witnessed any of this except it does seem to smoke a lot.
If you wan't to premix simply remove the pump from the engine case and make a metal cover to attach in it's place using a good hi-temp orange RTV and some screws.
No need to remove the oil pump drive shaft, just let it spin, if you want to you can remove it.
Also you want to plug the oil inlet on the block, you can use a vacuum nipple plug.
Once you remove the oil pump you can use the oil tank as a gas tank by running a short fuel hose from the oil tank to the reserve port on the fuel tank.
That means the oil gauge is now your gas gauge!
This means that you wont have a reserve feature on the fuel valve and that port on the valve should be sealed so when you use the "Prime" position will prime your carb and not spill fuel all over the place from the old reserve port.
This is all done under the seat and behind the fuel valve so if you dont want to mess with that stuff just leave it like it is and ignore the oil tank.
Sorry, I do ramble on.
I think this link will allow you to view the other pages I gave archived for the FA50.