I bought a 1984 big red 200es a little while ago and did the "new old" bike basics. vigorously cleaned the carburetor, and air box, also the fuel screen inside the tank along with the petcock. then tried it for spark which there was none, i fixed that. which was a broken connection on the stator for the spark generation, now i have spark and the bike starts right up every time first pull. when i go to drive it, she goes along in first fine then when i leave first she pops bangs and spudders to a stop
unless i pop it back in neutral, also when i put it in low gear and go she will go just fine, until i try to go past quarter throttle, to which it will pop and bang and want to shut off. it seems like weak spark, cause its only when shes under stress that she will die.

any help would be appreciated, I cant figure this one out.