I have a 2013 Cf moto 800-2 terralander atv. Replaced battery and spark plug and still wont start?

When was the last time it ran.

No on the timing..sounds like the carb needs a professional cleaning.. and replace the spark plug!!

filter in gas tank clogged or inline filter. injectors clogged? starving for fuel so check all fuel system.

Check the electrical connectors especially at the ECM.

Somewhere you have a bad connection. Trace the power line with a test light and find where you loose the current.

There is on most new ATVs an idle control valve it can be vacuum or electric i think yours is Electric its like a little valve with a spring it could be stuck or faulty depending on what the unit is doing .

Idle Air Control Valve ATV CF moto Valve UTV 400 500 700 HiSUN MASSIMO Hsun

Troubleshooting
If Check Engine will not start ·Battery has low voltage.
·Loose or corroded battery connections.
·Fusible link is melted.
·Spark plug wire is loose or disconnected.
·Faulty spark plug or coil.
·Fuel shut-off valve turned off (if equipped).
·No fuel or improper fuel.
·Plugged fuel filter.
·Defective starter solenoid.
·Open-circuit in wiring.

If you have no spark , check kill switches for corrosion, does the light work when u turn it over ?

( (terralander 800 atv wiring diagram ) serch on the net easy

Try replacing the solenoid, which is attached to the starter.
To test, run it until hot,let it sit for 5 minutes, try to start. Then, go and tap the solenoid with a hammer ,and try to start again. I bet you it will crank over.