Yfz 450 turns and turn but won't fire !!
 

Yamaha yfz450 turns and turns but won't fire up /sometimes when the engine start battery charger on it runs while I press on the gas but soon as I stop pressing the gas the engine cuts off.. but I think it has something to do with the neutral light not staying on, and another thing it won't turn unless the light switch is on🤔..need help please can someone point me in the right direction