I use nk900.26 variator naraku high-speed.Only half amount of metal,wich gets very hot.I also understood clutch contra spring.2000 rpm=20 gram weight,1500rpm=15 gram,1000rpm=10g.So I changed from 1500,to 1000 rpm because belt will not release,and engine rpm low.Because of many hills,I will soon test 500 rpm,so engine runs on higher rpm.SAME AS VARIATOR.