Like fiveliter. I noticed a smoother running engine with no performance gain. In my opinion, replacing the spark plug with an NGK, a quality coil, and cdi will give you a smoother firing, running engine. There was no gain in speed. Basicaly replacing stock with better quality parts. That particular CDI is way over priced for what you get, and is made for the Chinese clone GY6 engine.
Does Kymco put the GY6 engine in their scooters? I didn't think so
