Mini bike coleman ct200u wont start and kick backs when i pull the string

Have you cleaned the carb maybe the jets are blocked change the spark plug check the tank maybe the fuel has been sat awhile and don’t be scared to really pull the string not all the way out or you will break it be strong the pullback could be it trying to start but not enough momentum

If it has a kill switch maybe the problem

Or the spark cover is not on properly

Some times different weather can change the bikes performance (hot day No air) humid, it will need to be adjusted on the carb can be a air screw, or a fuel screw, probably not the problem

3 thing

Spark Fuel Oxygen

If one of these is out you will have a problem

To much fuel Black and wet spark plug, if running excessive fuel being spat out the exhaust, back fires Running too rich

Spark or no spark, maybe a weak spark plug or the CDI

Oxygen if you breathe too much on the bike you will then steal the oxygen from the bike so hold your breath, kick start or string GO MENTAL untill it starts and then breathe again If failure to START throw object on floor and tell it you mean nothing to me,