help until I can find a Manual

[Vecchio lupo]

Gentlemen ,

I am the new owner of a 1968 ES 175/2 Trophy (Yeah, the red one) , Im looking for a manual but in the meantime Im wanting to change fluids. I'm running 33-1 oil ratio that I learned here on this forum as well as use 1 liter of 85w90. Now my question is: I have three drain plug looking things on the bottom of my engine, from left side to right they are small/medium/large and there is what looks to be a filler almost above the middle (medium size) plug. If nobody knows off the top, I'll take pictures, so....which is the drain and what are the others?

Thank You, I love my MZ and I dont want to blow it up out of stupidity.

[Vecchio lupo]

BTW this is not my engine but some image off the great and all powerful intranet.

[Guesi]

The large is for oil draining, the other ones are for gearchange adjust. So don´t touch these unless you want to pull the engine apart..

[Vecchio lupo]

thank you, that is exactly what I needed to hear. I did order a manual but the unknown age and quality of gear oil concerns me. Again, thanks,