Sorry for reposting. I'm new to the site and forums. What I have is a Chinese 250cc. Sometimes it fires. Sometimes it doesn't. I have replaced the stator the coil The cdi box. Spark plug. And still no luck. I've checked all the connections and they seem to be good I've about had enough. Can someone help me please.

 

How did you test for spark? Is the cdi box ac or dc? Is the parts you put on it from amazon?