I just purchased a 2003 kfx80 that sat for many years. It’s in excellent shape and was never abused. I drained the gas, cleaned the carb thoroughly, and changed the spark plug. It cranks and will try to fire up every so often but just won’t start and run.

 

You might need to do a compression check. Did you pull the jets out and blow them out during carb cleaning.

 

Get anything figured out to get it started?