i don't think you can you will need to bye a new pull start or pull the cover of and find a piece of line that will go around the pully so you can start it
If your mini moto has gears...you can use a meathod called "popping it". it works 99 out of 100 timnes... someone gets on the bike and another person pushes it until it reaches a pretty fast...
If you are a good welder, make a piece to attach to the crank screw that would fit a "T" shape drill piece, then you can use an electric drill with the T piece, to start it.