There is a small breather hole that leads the crankcase pressure to the inlet, this hole can be blocked if the gasket is mounted wrong side up. **************************************************
I think this may be referring to the cylinder head gasket....Bells are ringing
I modified an older MD 2 by replacing a blank flange on the upper crankcase with one fitted with a 1/2 " pipe stub which was connected by hose to the air inlet.
Maybe you have a convenient blank as otherwise you might have to get your fella to remove the head and fit a new head gasket the right way round ..