It's possible you have the wrong oil bottle.

The stock MC16 oil bottle is a one piece design. I think later NSR's used the two piece bottle (I know the MC18 mkII does). Also the MC16 bottle is opaque black, whereas the MC18 one I have (and possibly other later models) is translucent beige. The MC16 one only sits on the outside of the frame, there is no part of it that goes under wiring tray.

Hope this info helps.