Hello!
Yes Paulo, up the motorcycle in a elevator or you stoop and see two plug but only one (the big) in an inclined position (the drain plug) like said Haynes book.
The engine must be heat -Careful with the skin burn-
Oil : 750 cc. SAE 80 EP
Manual MZ said (like said Thompson) alternative oil SAE 30W40. The problem this oil generally are formulated for car engine (dry clutch), the clutch can slip in the MZ and you must be change (no enougth change for correct oil) contamitated friction disc.
Manual MZ said also chage oil every 20.000 Kms!!

. Oil isn´t expensive, you can change (aprox.) every 5.000 km for long life and clean engine when you open to repair; oil for engine is like blood for us, (sorry for the obvious).
Saludos, Manuel