AFAM does make the correct sprocket. Part number is 52612-14. Just bought one with no drama from Drive Systems USA in Huntington Beach, CA. (I have no interest in that outfit.)
The correct sprocket has the same raised faces on both sides of the sprocket as the stock 15T one, not one flat side like the front sprocket the earlier carburetted M900 used.
Combined that front sprocket with a 41 tooth rear sprocket and stock 98 link chain fits fine.
Hope this info is useful.
