Baja ATV 50 Cranks But No Start

Hi everyone. My apologies if I'm posting in the wrong area. However my son and I are working on another project. We have a Baja 50 ATV. The problem we're having is that it will crank but doesn't start. Below is everything we've done so far.
1) Drained old Fuel-Filled with fresh fuel.
2) Drained Old oil-Filled with fresh oil.
3) Replaced CDI & Rectifier Regulator
4) Replaced Ignition-because it did not have keys for it
5) Checked Spark plug for Spark
6) Checked to make sure the fuel line wasn't blocked.
7) Checked Fuel Filter-Good
8) Checked Battery - All connections were tight
9) Checked Solenoid
0) Checked the emergency tethered kill switch, however we're not exactly sure about this because it doesn't push in or pull out, just spins. Can't tell just yet if that actually works or not.
Could anyway shed some advice on what we're missing or forgetting. I'd very much appreciated.

I would check for spark then for fuel. even though you drained old fuel it may have gummed up the carb depending on how long it sat.