Welcome to the forum Bohemian_Lady
When you fitted the piston back into the cylinder barrel how did you compress the rings so they would slip nicely into the bore. If you've broken a ring it might be caught in one of the ports in the cylinder barrel.
Are you sure that the new piston you replaced is the same as the old one because there are differences between engines made in different Chinese factories even if the engine is of the same capacity.
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