Where are the notches and what do I allign them to? How do I remove the chain and sprocket. I was down shifting last night and it cut off, Now I am backfiring through the carb with great compression. I am 99.9% sure its out of time but I need to know how to tell so I can check and replace. Do I need a certain type of chain since I have a bore and cam? Any help would be greatly app. Thanks

1999 Honda 400EX
40 Big Bore
Hot Cam Stage 3

PS I am wanting to go riding tomorrow and want to do this tonight so the sooner the better.