Hydro Hutch 36m

Hello, I am inheriting a 1978 DT 175 Enduro that needs a new crankcase cover. I will be getting my riding certificate soon and will be using the bike to get back and forth from work. However I want to get the cover before I take my rider's test. I've searched online but can't really find anyone that sells these. Can anyone give me some hints, suggestions, etc? Thank you, -Hutch