I have a raptor 660 that has an over bore wiseco dome high compression piston, Increased main jets, cleaned carbs, adjusted valves, but not able to get out of first it just sputters. What am I doing wrong? Please HELP

 

just for a short period of time and in a clean enviroment start it up with out the air cleaner. It almost sounds like it's not getting enough air flow. If that doesn't work try going the other way, increase the jetting a little more. I should have asked what the plugs look like?