I have a Polaris 250 mounted on a go kart. It is a bare bones set up right now. From the CDI box I'm getting a small glow(using a light tester) when checking fire from the black/yellow wire and a bright quick flash from the black wire, I can't get either to fire the coil. Bad CDI box or what?

 

Pull the black wire from the cdi first to eliminate it from the kil circuit. If it has spark,could be in the ignition switch,etc as to how you have this set up or possible that the cdi black wire is faulty itself internally. Wouldn't over look the stator as it could be the problem.Need the year model on the engine if you have it so I can give you some resistance checks on it.

 

I don't know much about the engine other then it's a Polaris 250, is there any visual indicators I can look for?