New member big problem

[Linhai260]

Hello everyone my name is Cameron I currently live in Arkansas an I currently own a 2006 linhai classic aeoules 260 170mm . My scooter Currently has 5800 miles on it . It has a very big unsafe problem with the engine cutting out at different throttle by cutting out I mean engine going from 3500 rpm to 600-1000 rooms with backfire and stuttering . Mods I have done include throwing out the stock air box for a pod filter taking the jet from 128 to 140 drilling holes in the exhaust for better flow (poor man's performance exhaust ) adding a 3 prong Chinese spark plug and took the cdi governor to 9k rpms with a new cdi . Does anyone have any ideas on what the problem could be if I flutter the throttle the rpm will come back for a short time then cut out again . It wants to die when stopping in less I flutter the throttle .