NARAKU sports variator for GY6 and 50cc Kymco 4-stroke engines as well as tuned Kymco/ SYM s-stroke engines. When calibrated, this variator provides good acceleration at higher speeds. The set comes with 6g Variator weights 16x13mm. These weights are suitable for scooters in original condition. If tuning components (e.g. exhaust system or counter pressure spring) are installed, we recommend that you re-calibrate the weights. We offer various kits and 16x13 weights.