[Big Bob1]

'13 CF moto 500 was rolled backwards down a hill with me last year.  ATV sat all winter while I healed, now I try to start it, no luck.  Battery is good, 12.7 volts, gas was unleaded premium,  and stabilized. When it ran there was always a humming/buzzing noise when you first turned key to run/start mode, that's gone.  When attempting to start the cable from positive Battery to starter relay mildly buzzes...ok ready for help and advice.  Thanks!!
Big Bob

[NMKawierider]

Re-check all the battery cable connections and do have the battery load tested. Inspect all fuses, connections and the kill switch as well as pull the plug for cleaning and see if it has spark...but it being a 2013 means its carbureted and it probably dried-out..which means it likely will need pulled, vatted and kitted.

[doug80638]

Does the starter/engine turn over but not start?

[Ulfthednar]

I believe that buzz/hum is the fuel pump pressuring up.

[murdo]

They don't have a fuel pump, gravity feed.
Open the drain plug on the carb and drain out the old fuel, then fresh into the tank.
Are you putting your foot on the brake when trying to start?