I removed my counter sprocket to replace with a 13 tooth after hearing so many positive reviews. When I finally got the nut off, I pulled off the sprocket and put it down then went in for dinner without paying attention to which way it went on. The sprocket is flat on one side and has a ridge on the other. It looks like it's supposed to go on with the ridge toward the bike, flat side out to mate up with the washer and nut.

Anyone with better memory than me know the correct direction?

 

the side with the raised boss goes towards the engine flat side out

 

^ What she said.