A quick chat about fitting the dreaded $2000 O'ring on my 1981 BMW R100 CS Restoration project.
Read This:
http://largiader.com/tech/filters/
http://largiader.com/tech/filters/canister.html
My Spreadsheet: Use this formula at your own risk; read the above pages FIRST.
https://fastupload.io/en/mEATLq5V2TR6Yda/file