Atc 200
It might be the carb. jetting. I know that you have to re-do jetting if you add any power adders. Bigger pipe=Bigger jets=bigger air filter.
Imo...Your main needle jet in your carb. is too small(diam.) or up to high. I'm not sure if 4-stokers have a c-ring clip on the main Needle jet but, if it does you have the c-clip to Low on the Needle jet(Rich). The further up you go the Leaner it runs.
*There's a pin in the cam that locks the spark advancer in place if that's not there the spark advancer wont spin and you'll have
no spark take the cdi cover off and see if its spinning...just a thought...
ATC rider Forever.....
