Hello. I replaced the front and rear sprocket on my 1994 TW200 and now it wont start. I had to take the side engine case off to get to the front sprocket. I am wondering if something isn't lined up correctly now for ignition timing. I am getting a spark out of the plug right as I let off the starter button, but it is not sparking as I hold it down. The motor will turn over, but not start. Am I missing something that should have been lined up for ignition timing? Thanks in advance for any help.