Fuel and spark, spark is easy to check. Is there fuel in the bowl? Is the idle screw adjusted for way too low of an idle? Anything happen if you give it a lil throttle while pulling on the cord? Is fuel unobstructed leaving the tank? I'd start with spark to verify. W/a HS usually it's a fuel problem.
1.When you got it did you drain and put fresh oil in it. cause i almost forgot lol
2. did you check to make sure plug was seated tight, had one come loose
3. is it getting fuel correctly have you tried with cap off, or even no filter
4. did you use choke or forget it on when you where riding
5. put idle all in give it a test if it runs bring idle down slowly