idles but will not rev

[clueless]

49cc taotao will start right up but will not rev past idle. when you twist the idle you can hear a change in the engine but stays at the same rpm. I have cleaned the carb, totally dismantled and rebuilt. put it back on and no change. put new carb on, same problem. completely tore down the new carb to check for issues, put back on and same thing. moved to valves, set and same thing. replaced the CDI with three others and nothing changed. I am beside myself and he doesn't know what to think of it either!!! can anyone help? thanks!

[clueless]

today I took the carb off my personal taotao and it does the same thing.
when this scooter came in, they had the oil filled to the top of the oil fill tube.

[Roscoe]

Could it be a clogged exhaust? If it's a 4 cycle check the valve adjustments.

[clueless]

i will check the exhaust!!! the valves checked and rechecked. thanks!

[clueless]

well here we go!!! new parts arrived to stock shop. I took another CDI one out of this shipment and POOF, it is now the smoothest scooter i have ridden. I then took the four prior (the one on it and the three new ones from older shipment) put them on my scooter and they did the same in my scooter, idle with no rev. they went to the trash! 3 out of ten in one order were bad??? thanks for the help guys!

[Roscoe]

The rev limiter on the CDIs were bad?