Z 440 H2 revival

Hello you, as I have already written in the oldie department, I would like to renovate my faithful Z 440 core. I already have the workshop manual in parts and a little basic knowledge. I hope for your help where the two things are not enough and come with two more or less stupid questions. On the one hand I am looking for a new seal for the starter cover, but can not find one in the whole WWW, only whole lid with seal. Does anyone have a tip where I can get the seal only – or should I go the easiest way and use sealants? My seal is definitely over, stone hard and also torn in several places, in one place completely through. Image I attach. The second thing I’m concerned about is a small plastic tube (I think to have found out through internet contributions that this should be my crankshaft ventilation, but let me be taught a better one), which lay loose in the air filter box and is too short to have it I also attach a picture to it. As I suspect that the tube should pass through the airflow, but it is too short to do so, here my consideration: extend one end with a suitable hose and then put the whole thing together – is this a good idea, do I not need that anyway or do I even lack a part, which still has to come to the tube? I already thank you in advance and Have a nice week.