The parts manager at KYMCO finally called me back today, say's he was out of town last week or he would have returned my call sooner. He checked with KYMCO Taiwan who said the part they shipped was compatible even though the part #'s were different. The new filter is shaped a little different so it does not mount as secure but after installing it and firing the scooter up, problem solved, backfire gone. If I had replaced this part 4 months ago I could have saved myself the purchase of a new muffler (($270) but you live and learn. The important thing is that my scooter is back on the road and with morning temps dropping into the 30's I can park my nearly naked Buell.
Axy, you win the prize. Thanks for the advice!!!