CT: While your still here, the Continental GT 250 is a Unit Construction engine.
It doesn't have a separate drain for the transmission. The engine oil is the transmission oil and most likely the primary drive chain oil too.
I suppose you are not pulling in the clutch lever when you try to use the kick starter?
If the clutch lever is pulled in, the kick starter won't work.
It would be really good if you restarted this post in the forums Vintage section.
That's where we talk about the old Royal Enfields.