You should e-mail the CIK and ask if it is possible, what paperwork you would have to complete and the cost. There are some regulations regarding having the manufacturers signature which if applicable would probably be impossible to get.
Like with the 256 tandem twin although that too was a grand prix engine from before 2001, the CIK withdrew it’s homologation last year, so that it can no longer be raced in CIK/FIA events like the European Superkart Championship. But in the UK we still allow the Rotax 256 in our National events.
As I said, I would be interested in the engine for use in a motorcycle.
No, the revised EKN forum is not so easy as the old version.