A new original carburettor (ZAMA C1M-S141C) wasn't available for the BG86 (not my machine). A replacement (equivalent to ZAMA C1M-S261B) had an extra pipe to direct vented fumes into the air filter, to meet emission laws I assume. The filter housing had the position for the vent pipe already marked. Actually I did find a Stihl branded carb without the vent pipe for about £100, but that was too expensive.
