Sunn Obsys suspension forks: manual

[Anders Bro Byst]

A friend of mine has two of these French low-travel forks that both needs service. He has new seals
but no idea about oil level, weight etc. I can't find anything on the web. Anyone has a manual - or
knows about oil level and oil weight and whatever you should know to service these forks?

Thanks in advance! Anders (from Denmark)