I'm stumped on this one. A few days ago, I rode about 5 miles on the bike without a problem. Today I went to start it up and it started (with choke), but died with a little puff when I twisted the throttle. I started it back up, let it run for five minutes, but it still died when I gave it even a tiny bit of throttle. I'll clean the carb and check the fuel filter. The air filter is good.
I'm afraid it could be the timing. Listing to it, there is a click on each stroke. Here's an MP# of the bike running until I give it a tiny bit of throttle: http://brownelearning.org/tmp/puttputtdies.mp3
Any other ideas?