I have '04 Lifan LF250ST. 2cylinder twin carb 250cc.The carbs on it are Keihin CVK. Went thru the usual spring ritual of pulling carbs off and cleaning them out. Changed fuel lines from tank as well as the filter.It starts ok runs for awhile till engine warms up then dies, while it is running does not want to take any throttle,bogs and sputters. After it shuts down it does not want to restart. Checked and have spark at the plugs. I'm just not sure if it is fuel or electrical ( CDI box) related.
Any info would be appreciated.

 

To me, sounds like fuel. Get good flow out the fuel line if you pull it off the carb?