NCY Roller Weights 18mm X 14mm COMPATIBILITY: BMS 150cc Scooters / Go Karts Coolster 150cc ATVs / Go Karts Diamo 150cc Scooters Kymco 150cc Scooters Lance 150cc Scooters PGO / Genuine 150cc Scooters Roketa 150cc Scooters / Go Karts Tank 150cc Scooters TNG 150cc Scooters Many Other 150cc GY6 Based Engines We highly recommend that you begin by upgrading the variator roller weights before engaging in any performance upgrades. This is the simplest of upgrades and the least expensive. This is a minimal investment and offers a maximum return. The main rule for tuning variators is the lighter the roller the more rpm’s are needed to push the rolls outwards through centrifugal motion to set the gear change in motion. Heavier roller weights need lower rpm’s to start moving. Heavier roller weights = slower take-off speed, more acceleration = higher maximum speed. Lighter roller weights = faster take-off speed, less acceleration = lower achievable speed. The right balance is an individual choice since a scooter racer will want heavier weights to achieve a higher overall speed so that they might be faster at full throttle. For daily use a rider might prefer lighter weights for more power to take off faster at stop light. **