What was found
A MODIFIED BRACKET AIR FILTER ELEMENT DELAMINATED AND WAS SUCKED INTO THE CARBURATOR, BLOCKING THE AIR FLOW. THE AIR BOX HOLDING THE MODIFIED AIR FILTER ELEMENT DID NOT HAVE A SCREEN GUARDING THE ENTRANCE TO THE CARBURATOR AIR INTAKE DUCT AS IS COMMON ON CERTIFIED ACFT. THE ACFT OWNER MODIFIED THE DESIGN TO INCORPORATE A SCREEN TO PREVENT A REOCCURANCE AND INFORMED THE BIPLANE ASSOCIATION OF HIS FINDINGS AND RECOMENDATIONS.