..ever tried measuring the distance between the driven pulleys , z ??
Not with a tape but I had 4 belts, and took the contra/rollers out to find the belt that sat right everywhere. The Malosi 1153 is the one that works with the current set up. The next one up I forget but it works with a 110mm var in mine. Less take off but about 4 mph top. I may use it when I run the bike for mph, and stay w/ the 1153/jasil var for weekends.