You need to mix 40 to 1 petrol oil mix ( Castrol power 1 racing 2 stroke oil )
EP 80 gear oil or car engine oil in the gear box ...with my old HE R80 I used to flush the gear box a few times with clean oil , then drain and put the stated amount in after. I believe it only required 20ml of oil from empty but check with HE paramotors first . If you email them they are quick to respond.
My R80 was a nice smooth motor and very reliable but I chose to change it after gaining some experience and my belly required more power.
I have an older grease filled 80 gearbox on the shelf if you are ever stuck.