We are all wise after the event, but next time......always put the r/h cylinder on tdc before playing with timimgs.
Then pull off the covers and observe the position of the various sprockets, marking the 6 and 12 position as mentioned above, also, do the timing (ignition sorry) bean can too, mark it so that it can be replaced exactly as it was removed.
I have an old barnyard R65LS that I will be playing with when I get home (I work in China), so I too will have to do what I say above. I have had many BM's in the past, you really have to think ahead on almost anything that you do with them, certainly they are simple to work on, but they are not simple to do many jobs unless you follow a few basic engineering principles. Pics before and after with todays digital cameras a re great.