NARAKU 16x13 ROUND ROLLER WEIGHTS FOR 50cc - 100cc 4-STROKE QMB139 ENGINES GEAR RATIO IS CHANGED BY THE UP-AND-DOWN ROLLING MOVEMENT OF THE ROLLER WEIGHTS NOW THE INNOVATIVE NARAKU ROUND ROLLER WEIGHTS ROLL UP AND DOWN THE RAMP TO CHANGE THE GEAR RATIO. THIS UNIQUE ROLLING MOVEMENT PROVIDES EXCLUSIVE ADVANTAGES TO INCREASE CVT PERFORMANCE. WITH DR. PULLEY, NO ABNORMAL WEAR WILL OCCUR EVEN WHEN RUNNING IN HIGH GEAR. WE RECOMMEND STARTING PERFORMANCE UPGRADES BY CHANGING THE VARIATOR ROLLER WEIGHTS FIRST. HEAVIER ROLLER WEIGHTS= A SLOWER TAKE OFF SPEED WITH LESS ACCELERATION AND A HIGHER TOP SPEED. LIGHTER ROLLER WEIGHTS = A FASTER TAKE OFF SPEED WITH MORE ACCELERATION AND LOWER TOP SPEED SIZE: 16 X 13 SET OF 6 LASTS LONGER THAN STANDARD ROLLER WEIGHTS EXCELLENT HEAT RESISTANCE LOW FRICTION / LOW WEAR FITS MOST MODELS OF TAO MOTORS, WOLF, ICE BEAR, JONWAY, JMSTAR, ROKETA, SUNL, TANK, PEACE, TAOTAO, GATOR AND MANY OTHERS