Dr. Pulley Sliding Weights 18mm X 14mmCOMPATIBILITY: BMS 150cc Scooters / Go KartsCoolster 150cc ATVs / Go KartsDiamo 150cc ScootersKymco 150cc ScootersLance 150cc Scooters PGO / Genuine 150cc ScootersRoketa 150cc Scooters / Go KartsTank 150cc ScootersTNG 150cc ScootersMany Other 150cc GY6 Based EnginesWe 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