Won't Start

Lately I’ve been riding it a lot more and it’s been running fine up until yesterday.

I went to the store, killed the engine, and went inside. When I came back out, it started up normally and ran fine around the parking lot. Then all of a sudden it sputtered and died.

I tried bump-starting it a few times (dumping the clutch) but it wouldn’t fire back up.

After testing today, I’ve confirmed it has spark, compression, and fuel. The carb is clean and is spraying a solid mist of fuel. It’s running a 30:1 fuel/oil mix with an NGK B7HS plug.

There are no obvious air leaks that I can see. Intake and exhaust are both mounted properly, and all gaskets are intact.

At this point I’m not sure what’s stopping it from starting—it just cranks but won’t turn over.

(It makes a weeeeeeeeee sound as it dies slowing down after clutch dumped.)