i have a indy 400 i just put new crank seals piston and rings and rebuilt the pump and cleaned the carbs and put new fuel lines on and put a new stator and still wont rev if i work the throtle i can get it to start to rev but then it will back fire could it be the cdi ?
Sounds to me like it might be lean. Flip it on halfchoke and see if it improves at all. If it does, feed it a bunch more fuel at the low end. Raise your needle, crank open the fuel screws, and clean the pilot jets again. See if that does anything. Try to eliminate fuel problems before you jump to ignition. Did you check the fuel pickup filter that's inside the tank? Those things rot off or plug up too. That could lean you out also.