Don't use cheap oil. Change the oil and filter with a good synthetic (Mobil 1 or Amsoil motorcycle oils IMO) and you will be fine, maybe do an early change next change.Swap the the coil wires from side to side, both sets, the ones that power the coils and the ones to the plugs. If the problem changes sides you probably have a bad coil. If not you have a bad CDI.

I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!