I understand that you have a problem. But your terminology is confusing. If you can, pictures would be a great help. I assume you meant fa50? Treatland.tv is the main moped parts supplier. Along with doscycles.com
From you description it sound like it could be a wedged in gasket, a seized cylinder, jammed rings......it's just hard to tell what you mean.
Also, alot of people here are teens.lol you'll figure it out don't get discouraged. (edited)