it is very common for the oil injector to plug or just stop working. when this happens there is no oil being mixed in with your gas. in order for your bike to run there has to be 2stroke oil mixed in the gas which is usally done from the bottle under the seat. when that plugs and you run it straight gas it will blow up. people by the oil injector block off kit and just premix the gas. really easy to do. buy a premix measuring cup and mix oil and gas. 32:1 is most common.