The isn't really any proper drawings available for models with central oil tanks. There was a thread here previously where it was mentioned that the UK NOC was in possesion of a huge cache of original drawings which they somehow acquired that may have those drawings among the batch, but legalities, politics, and money are all involved in the claim of legal possession. It's too bad because having those mechanical drawings is helpful in visualizing "what goes where" and seeing how the system works.
I just got back from a one hour ride up in the hills on my newly transformed '70 interstate model. I believe it's a one of a kind... Pffffffffffft, of course it is. I'm much happier without the old triangular side covers banging up against the bottom edge of the interstate tank, and having the stupid key on the face of the sidecover sticking out in the wind... Once I get the decals for the side covers I'll post pictures of my '70 in interstate clothing.
On this page of AN's website:
https://andover-norton.co.uk/en/shop-drawing/489/oil-tank-battery-tray-air-filter-1969-70-r-s- , You can see the parts list and picture of the parts and glean the information about the oil tank washer requirments. Both banjo fittings have 2 washers, one washer against the tank, and one washer against it's bolt.
