I would look at things in this order
1- flywheel key
2-flywheel itself
3-crank phase
If its not the reeds my next thought is that it is firing at the wrong time.
Is it doing this all the time now? Meaning its not longer doing it intermittent and each time you start the bike and try to drive away it does it?
Does it seem to vibrate worse than normal or seem lazy when you rev it?