Do you have to do anything to your atv when you get a aftermarket cdi or can you just leave the engine stock? thinks.

 

You dont have to do anything but, depending on what quad you have you most likely will not see any performance gains by adding just a new cdi to a stock engine. In fact you may even over rev it therefore damaging your engine is also a factor. I would spend the money on something you can actually benefit from (JMO).