I've had both problems, an oil leak in the area of the countershaft sprocket and excess chain lube. From the photos and your description, this looks exactly like excess chain lube. Oil leaks usually end up running down to the oil filter and then back to the side and center stands. The bottom of the bike will have oily (not just dirty, but oily) residue. Chain lube looks exactly like your photos. I had to learn to use less lube. Take the cover off and look inside--it's probably a waxy, gritty mess, as is the area around the sprocket. Clean it up with kerosene, go easier on the lube, and I bet you're fine.