The depth of this part is approx 6 cms. It’s a kind of contiuation of the top half of the petrol tank. If you look at image 2 above, the widest part is 21.6 cms but it has been dented a little bit. Where it’s narrower, it’s 19 cms. But basically, it’s a continuation of the petrol tank but slopes down a little. In your image, there’s a kind of ‘braket’ with two holes which fit in with two holes in the side of the cover which is seen above. Maybe I should have taken a photo of these holes.
I had some trouble becaue a niece of mine has taken my usb wire beloning to my phone so I had another niece taking this pics suing here iphone which I don’t understand. If you need any more information I’ll try and help.
Would it be possible for you to take a pic of the removable screw to show the oil level or point to it on your photo? I can’t see it at all.