I located your posting while doing a "search" and wanted to "thank you" for clarifying the oil drain plug location.
The manual and other postings on the subject refer to the drain plug containing the oil screen, which after your remark regarding its location near the left foot peg, I was finally able to see it.
Your posting was the first that I had found which referred to the "other" oil drain plug located on the bottom near the center of the engine.
I had the oil changed at a motorcycle shop last year then I bought my 1991 Kawasaki 750 Vulcan, I was never happy because I could not see the oil in the oil level gauge.
This year I did the oil change myself, mainly to see how much oil was in the engine, not changing the oil filter and using the drain plug on the bottom of the engine to drain the oil.
To my surprise I drained out over 5 liters of oil, and refilled with 3 1/2 liters of oil but I still cannot see any indication in the oil level gauge.
I now understand why previously , I was unable to see the oil level... it was over filled, but don't understand why with the correct amount of oil in the engine, there is no indication of the oil level in the oil level gauge.
Do you have any suggestions ?