Has your air cleaner box got an oval or round hole where the rubber connects? The longstroke engine should be round hole.
I bought some from this bloke he makes them for A10 and A7.
JEFF HUNTER ENGINEERING
Specialising in Reproduction Rubber Components to Original Specifications
35 Sandgate Road
Hall Green,
Birmingham,
B28 0UN,
ENGLAND
jeffalanhunter@aol.com