Impressed if you found an online manual which I couldn't, (though its a long time since I looked, and I wasnt very motivated since I'm unlikely to be doing much work on it),

If that 800ml is accurate, overfilling is likely, since I chucked the whole (litre) bottle in.

Bit doubtful though since

(a) Thats what the "black hands" (skilled professional scooter shop technical specialists) do, though likely the bottle is sometimes a US quart, which apparently is about 950 mls.

(b) I removed the plug at the bottom of the sump to clean out the wire mesh oil strainer, which the black hands dont do, so the engine would be more completely drained than it would be on a standard oil change, and so require more oil.

Could you post a link to the manual?

As I said, I'm unlikely to be doing much to it, but I'd like to confirm that you cant check the oil level, a barely credible b***** awful design feature on something that old, which gives me the feeling I must be missing something.