I have been building my osprey now for a wile and I pleased to inform you all that it is nearly done. I have a top tip and it is for exhaust gaskets for brigss/kohler are not readily available and are expensive. So the top tip is. Scooter exhaust gaskets just take you old gasket or draw around the exhaust flange and choose the nearest one from the scooter /bike shop.
I just got 4 for 6 and are easy to adapt with a drill/ dremel .