I rebuilt my 350x engine 1mm over (82mm) 10:25 to 1 wiseco , mid range cam , hardened rocker , stiffer valve springs . Before the rebuild I was running a stock 350x engine with a 300ex carb 40 pilot jet , 140 main , needle clip in the middle groove . My bike ran great . Rebuilt the engine and installed a 400ex carb 40 pilot 140 main needle in the middle groove . Could not get the bike to start . Everything is clean on the carb no clogged jets or passages . I took the carb boot off and could see the accelerator pump shooting gas into the intake . I put the 300ex carb back on the rebuilt engine and the bike started ? I wanted to run the 400ex carb I know its not to big of a carb because alot of people run them on 350x engines . I changed the pilot to a 38 and still no difference . confused in Ohio ?